Abstract: A method of reducing fluorescent self-quenching comprising attaching fluorescent molecules to nanoparticles so as to thereby reduce the self-quenching of the fluorescent molecules, the resulting fluorescent nanoparticles, and solutions that comprise such fluorescent nanoparticles.

Abstract: Polysiloxanes having vinyl or epoxy functionality. The polysiloxanes are used to form polymer-based materials having properties particularly suited for biomedical device applications. The polysiloxanes are of general formula I: wherein R is a C2-10 alkenyl, a C2-10 alkyl with an epoxy group or a C5-C7cycloalkyl with an epoxy group; R2, R3 and R4 are each independently selected from the group consisting of hydrogen, C1-4 alkyl, C1-4 fluoroalkyl, optionally substituted phenyl and optionally substituted benzyl; A is —OH or —NHR5, wherein R5 is hydrogen or a C1-3 alkyl; and B is —R1-A or —R6, wherein R1 is a linking group having an alkylene group with 2 to 8 carbon atoms wherein the alkylene group optionally includes ether, urethane or ureido linkages; and R6 is selected from the group consisting of C1-4 alkyl, optionally substituted phenyl or optionally substituted benzyl; and m and n are integers with an m:n ratio from 30:1 to 3:1.

Abstract: The present invention generally relates to pre-polymer and polymer compositions that can be photopolymerized. In one embodiment, the present invention relates to crosslinking agents that can be used in the photopolymerization of the pre-polymers and polymers disclosed herein. In another embodiment, the present invention relates to processes for producing pre-polymer, polymer and crosslinking compositions useful in photopolymerization reaction schemes. In one instance, the pre-polymers and polymers of the present invention can be crosslinked via a suitable crosslinking agent to produce networks (e.g., amphiphilic networks and/or co-networks).

Abstract: An asymmetric organomodified disiloxane surfactant having the formula: MM? wherein M comprises branched hydrocarbon substituents and M? comprises a cationic, anionic or zwitterionic substituent and a polyether substituent that may be combined as one moiety, wherein the disiloxane surfactant has an enhanced resistance to hydrolysis between a pH of about 3 to about 12.

Abstract: A process for preparing ?, ?-functional siloxane compounds in a purity of greater than or equal to 90% includes contacting a monohydrosiloxane compound of formula 1 with oxygen in the presence of a platinum group catalyst, without adding water, to form the ?, ?-functional siloxane compound in a purity of greater than or equal to 90%; wherein n is 0, 1, or 2; R1 is fluoroethyl, methyl or phenyl; and R2 is substituted alkyl, epoxyalkyl, oxetanylalkyl, substituted oxaalkyl, epoxyoxaalkyl, oxetanyloxaalkyl, alkenyl, alkylalkoxysilyl, substituted alkylaryl, and substituted arylalkyl.

Abstract: Disclosed is a method for activating a solid support material with epoxy groups and for immobilising ligands thereon, utilising phase transfer catalytic conditions. The method permits the introduction of epoxy groups and specific nucleophilic ligands on the support material with a high level of substitution. Furthermore, the invention provides a general method for immobilising a ligand for use in a wide variety of chromatographic separation procedures such as ion exchange chromatography, hydrophobic interaction chromatography (HIC), reverse phase chromatography (RPC), or affinity chromatography.

Abstract: A multi-functional silsesquioxane, method of making the same, and coatings incorporating the same, including a polyhedral silsesquioxane including at least one first face and at least one second face that is spaced apart from the at least one first face; at least one first functionality bonded to the at least one first face; and at least one second functionality different from the first functionality, and being bonded to the at least one second face. In one particular respect, silica for the silsesquioxane may be derived from rice hull ash via an octa(tetramethylammonium)silsesquioxane octaani{dot over (o)}n.

Abstract: Disclosed herein is a composition comprising a structure (M1)a(ME)b)D1)c(D2)d(T)e(Q)f, wherein M1=R1R2R3SiO1/2; ME=R4R5RESiO1/2; D1=R6R7SiO2/2; D2=R8R9SiO2/2; T=R10SiO3/2; and Q=SiO4/2; wherein each RE is independently a monovalent hydrocarbon radical containing an epoxy group; R9 comprises a structure -L1-Si(R11)g(OR12)3-g or L2(D3)h(M2)i-L3-Si(R13)g?(OR14)3-g?, wherein L1, L2, and L3 are independently divalent linking groups; g and g? independently have a value from 0 to 2; M2=R15R16R17SiO1/2; D3=R18R19SiO2/2; wherein R1, R2, R3, R4, R5, R6, R7, R8, R10, R11, R12, R13, R14, R15, R16, R17, R18, and R19 are independently monovalent hydrocarbon radicals; wherein a, b, c, d, e, f, h, and i are stoichiometric subscripts that are zero or positive subject to the following limitations: b has a value of 2; d is greater than or equal to 1; when (a+c+e+f) is equal to zero, (b+d) is greater than or equal to 3; and when i=0, h is at least 1.

Abstract: An efficient new route for the preparation of dihydroeponemycin, an active eponemycin derivative, is provided, which includes the synthesis of the intermediate compound, a hydroxymethyl-substituted enone. In addition, a method is provided for synthesizing inhibitors, which includes PI?-modified analogues. These analogues selectively bind to a major immunoproteasome catalytic subunit LMP2 and inactivate its proteolytic activity in a method of treating diseases, including myeloma and other cancers, Huntington's disease and Alzheimer's disease.

Abstract: The method consists in hydrolysing an initial volume Vse of a precursor material comprising at least one polyalkoxysilane with a quantity of water such that x ? ? H 2 ? O x ? ? Si ? 10 , ? and where x H20 and x Si represent the number of moles of H20 and Si present, respectively, the concentration of the hydrolysate up to a volume substantially equal to the initial volume Vsi, leaving the concentrated hydrolysate until segregation into an aqueous phase and an organo-silicon phase, and recovery of the organo-silicon phase. A product can be obtained which comprises an organo-silicon sol comprising silicon species T1, T2, and T3, wherein the molar fraction of species T2 is equal or greater than 50%, comprising a condensation rate equal to or greater than 0.65, and further defined as lacking water, as determined by analyzing a sample of said organo-silicon sol by 1H NMR and observing the absence of peak corresponding to water.

Abstract: The present invention relates to an organo-functional polysiloxane of formula (1) wherein each R1 is independently selected from alkyl or aryl radicals, each R2 is independently selected from hydrogen, alkyl or aryl radicals, n is selected so that the molecular weight for the organo-functional polysiloxane is in the range of from 400 to 10,000, R3 is a bivalent radical or —O—W—(X)z is hydroxy or alkoxy, z is 1, 2 or 3 and X is a reactive functional group for reacting with amine radicals and wherein 0 to 90% of —O—R3—(X)z is hydroxy or alkoxy

Abstract: The present invention relates to compounds having the structure (and pharmaceutically acceptable derivatives thereof) wherein R0–R4, Z, X, A—B, D—E, G—J, and K—L are as defined herein, the synthesis thereof and the use of these compounds as therapeutic agents.

Abstract: A compound of the general formula: R1R2R4MR5, wherein R1, R2 and R4 are independently an aryl, alkyl, alkenyl or alkynyl group, wherein at least one of R1, R2 and R4 is fully or partially fluorinated, wherein M is selected from group 14 of the periodic table, and wherein R5 is either an alkoxy group, OR3, or a halogen group, X. This compound formed can be further reacted to attach an additional organic R group, and/or hydrolyzed with one or more similar compounds (preferably having one or two R groups bound to M), to form a material having a molecular weight of from 500 to 10,000, which material can be deposited on various substrates as a coating or deposited and patterned for a waveguide or other optical device components. Methods for making and using compounds of the general formula R1R2R4MR5 are also disclosed.

Abstract: Versatile synthetic methodology has been established for the production of a variety of siloxane and silane-containing radial epoxy resins and intermediates. This chemical approach has been exploited to obtain a variety of hybrid organic/inorganic materials that can be described as epoxysiloxane or epoxysilane radial copolymers. The methodology can be used to access reactive, hydrophobic Si-containing resins with good organic compatibility that are structurally distinct from epoxy-functional siloxanes/silanes known in the prior art. These hybrid radial epoxy resins may be utilized for a variety of adhesive and coating applications including radiation and thermally curable sealants, encapsulants and adhesives.

Abstract: An organosilicon precursor for vapor deposition, e.g., low pressure (<100 Torr), plasma-enhanced chemical vapor deposition (PECVD) of a low k, high strength dielectric film, wherein the precursor includes at least one of: (i) silicon-pendant oxiranyl functionality; and (ii) a disilyl moiety of the formula wherein x is an integer having a value of from 0 to 4 inclusive. These precursors are useful for the formation of dielectric films having dielectric constants on the order of ˜3 and less, and a hardness exceeding ˜1 GigaPascals.

Abstract: A synthesis is described for intermediates which are readily amenable to the large scale preparation of hydroxyethylurea-based chiral HIV protease inhibitors. The method includes forming a diastereoselective epoxide from a chiral alpha amino aldehyde.

Abstract: Disclosed is a holographic recording medium. The novel holographic recording mediums disclosed herein comprises: a) at least one polyfunctional epoxide monomer or oligomer which undergoes acid initiated cationic polymerization. Each epoxide in the monomer or oligomer is linked by group comprising a siloxane to a silicon atom and each monomer or oligomer has an epoxy equivalent weight of greater than about 300 grams/mole epoxide; b) a binder which is capable of supporting cationic polymerization; c) an acid generator capable of producing an acid upon exposure to actinic radiation; and optionally d) a sensitizer.

Abstract: The invention relates to a heat-activated initiator for polymerising and/or cross-linking polyorganosiloxane-type monomers, oligomers and/or polymers with organofunctional groups, comprising a boron derivative of formula (I): (A)xB(R′)y, wherein the symbols R′ are the same or different and represent an alkyl or alkenyl radical in C1-C12, an alkoxy radical in C1-C12, a phenyl radical substituted by at least one electroattractor element, an aryl radical containing at least two aromatic rings such as biphenyl, naphthyl, optionally substituted by at least one electroattractor element, especially a halogen atom (particularly fluorine), or an electroattractor group, especially a CF3, NO2, CN group; and a radical —C2H4—Si(Q)3 with the symbols Q being the same or different and representing an alkyl or alkoxy group in C1 to C10 or a siloxane oligomer with less than 10 silicon atoms. The invention also relates to a corresponding cross-linkable composition and to the uses thereof.

Abstract: The invention relates to a method for the production of hydroxyalkyl polysiloxanes of general formula (V) (SiO4/2)k(R12SiO3/2)m(R12SiO2/2)p(R13SiO1/2)q[O1/2SiR3213 (CR42)b—OH]s[O1/2H]t (V), wherein organosiloxanes of general formula (VI) (SiO4/2)k(R1SiO3/2)m(R12SiO2/2)p(R13SiO1/2)q[O1/2H]r(VI) containing silanol are made to react with compounds having at least one unit of general formula (IV) [O—(CR42)—SiR32]n— (IV).

Abstract: Certain compounds within the general formula (I) 1

Abstract: The method consists in hydrolyzing an initial volume Vsi of a precursor material comprising at least one polyalkoxysilane with a quantity of water such that x ⁢   ⁢ H 2 ⁢ O x ⁢ Si ≥ 10 where x H2O and x Si represent the number of moles of H2O and Si present, respectively, the concentration of the hydrolysate up to a volume substantially equal to the initial volume Vsi, leaving the concentrated hydrolysate until segregation into an aqueous phase and an organo-silicon phase, and recovery of the organo-silicon phase.

Abstract: In a fluorosilicone rubber composition comprising (A) an organopolysiloxane having trifluoropropyl and (B) a silica filler, there are included (C) an organic peroxide of percarbonate type as a crosslinking agent and (D) a compound having a molecular weight of up to 10,000 and bearing in a molecule at least two substituents selected from among allyl, acryloyl, methacryloyl, epoxy and alkoxy groups as a co-crosslinking agent, whereby the vulcanization molding time is substantially reduced without detracting from physical properties.

Abstract: Compounds containing vinyl silane and epoxy functionality can be used as adhesion promoters or the main resin in curable compositions.

Abstract: Substituted tetrahydro-naphthalenes and analogous compounds are prepared by reducing or condensing appropriate functional substituents in substituted tetrahydro-naphthalenes and analogous compounds by customary methods and converting functional groups in this manner into the desired groups. The compounds according to the invention are suitable for use as active compounds in pharmaceuticals, in particular in pharmaceuticals for treating arteriosclerosis and also dyslipidaemias.

Abstract: A nonsagging and extrudable room temperature curable silicone rubber composition with excellent adherence to a variety of substrates comprising (A) diorganopolysiloxane having silicon-bonded alkoxy in molecular chain terminal position, (B) surface-hydrophobicized dry method silica, (C) non-surface-hydrophobicized dry method silica, (D) alkoxysilane, (E) an organotitanium compound, and (F) light stabilizer and/or UV absorber.

Abstract: Disclosed herein are a silane coupling agent and a method of preparing the same useful for a composite organic-inorganic material. The silane coupling agent is represented by the formula of R1R2R3Si—X, wherein R1, R2, and R3, respectively, represent straight or branched alkyl having 4 to 22 carbon atoms, alkoxy, phenyl, phenyl alkoxy, benzyloxy or phenyl alkyl group. The method comprises the steps of: dissolving a vinyl derivative in a solvent under a nitrogen or argon atmosphere; and reacting the resulting solution with an alkoxysilane derivative at a temperature of 20 to 200° C. for 1 to 72 hours in the presence of a metal catalyst. Alternatively, the method comprises the steps of: dissolving alkylmagnesium halide in a solvent under a nitrogen or argon; and reacting the resulting solution with haloalkoxysilane at a temperature of −78° C. to 50° C. for 0.1 to 5 hours.

Abstract: Silicone rubber compositions comprising (A) an organopolysiloxane having at least two silicon-bonded alkenyl groups, (B) finely divided silica, (C) an adhesive component, (D) a silicone-soluble organopolysiloxane resin component bearing at least one alkenyl group, (E) an organohydrogenpolysiloxane containing SiH groups in a specific mole ratio to the alkenyl groups in components (A) and (D) combined, and (F) a platinum group catalyst, exhibit excellent adhesion to synthetic woven fabrics for air bags. When coated onto woven fabrics and cured, the compositions provide air bag base fabrics of outstanding flexibility, sealability and deployability which remain stable over time.

Abstract: A silicone rubber based coating composition for air bags comprising about 0.1 to 50 wt % of spherical powder with an average particle size of about 10 &mgr;m to 300 &mgr;m.

Abstract: The invention relates to block copolymers of the general average formula with siloxane blocks which are linked via rigid spacers, and to their use as surface-active agents.

Abstract: An improved coating comprising a coating on a substrate is described. The coating comprises a crosslinked polymeric material derived from an alkine-bridged bis-(aminosilane) or comprising a mixture of the alkine-bridged bis-(amino-silane) and an epoxysilane. The alkine bridged bis-(aminosilane) may have the general formula: wherein R1, R2, and R3 are independently selected from alkyl groups of 1 to 4 carbon atoms or phenyl groups, R4 is selected from hydrogen, phenyl groups, and alkyl of from 1 to 4 carbon atoms, and m is 1, 2, 3 or 4. The alkine bridged bis-(aminosilane) is itself a novel compound. A novel coating composition comprises a coating composition comprising a solution comprising and epoxysilane and an alkine-bridged bis-(amino-silane), especially where the alkine-bridged bis-(amino-silane) has the general formula: wherein R1, R2, and R3 are independently selected from aliphatic groups or aromatic groups which complete a silane, and m is 1, 2, 3 or 4.

Abstract: A process for preparing epoxysilanes by reacting a hydrogensilane with an allyl glycidyl ether in the presence of a catalyst and working up the crude product obtained, where the catalyst is removed from the crude product and the crude product is subsequently distilled.

Abstract: Polymerizable siloxane oligomers comprising a plurality of repeating units of formula A and at least one unit of formula B: and terminating in a residue R2 or R8 are disclosed. In these formulae FG is a functional group, such as 2-(3,4-epoxycyclohexyl), and the R groups are alkyl, aryl, haloalkyl, aralkyl, alkoxy or aryloxy of 1 to 10 carbons. Processes for preparing the oligmers by hydrolysis/condensation of monomers of formula (RO)3Si FG and one or more alkoxy silane monomers of formula R3R4R8SiOR2a are also disclosed, as are polymers resulting from the cationic polymerization of the oligomers.

Abstract: A synthesis is described for intermediates which are readily amenable to the large scale preparation of hydroxyethylurea-based chiral HIV protease inhibitors. The method includes forming a diastereoselective epoxide from a chiral alpha amino aldehyde.

Abstract: The present invention relates to multifunctionalized polyorganosiloxanes comprising, per molecule at least one functional siloxy unit Y having C1-C5 alkoxy radical and at least one other functional siloxy unit W having an halogenated or polyhalogenated alkyl, aralkyl or aryl; polyether ether; epoxidized alkyl; alkoxyalkyl; hydroxylated, carbonylated or esterified alkyl; phenol; and alkoxysilyl; and optionally at least one siloxy unit having a SiH group. The alkoxy functionality Y is introduced onto a suitable polyhydroorganosiloxane by a dehydrogenation/condensation reaction from the alcohol from which Y derives and then the non-hydrogen functionality W by a hydrosilylation reaction from the olefinic compound from which W derives. The multifunctionalized polyorganosiloxanes can be used as antiadhesion modulators in silicone compositions.

Abstract: The present invention provides a coating composition which comprises at least one silicon compound (A) which has at least one radical which is bonded directly to Si, is not able to be separated hydrolytically and contains an epoxy group, a particulate material (B) which is selected from among oxides, oxide hydrates, nitrides and carbides of Si, Al and B and of transition metals and has a particle size within the range 1 to 100 nm, a Si, Ti, Zr, B, Sn or V compound (C) and at least one hydrolysable Ti, Zr or Al compound (D), which comprises the following ratio 1 mol of the silicon compound (A), 0.42 to 0.68 mol of the particulate material (B), 0.28 to 1.0 mol of the compound (C) and 0.23 to 0.68 mol of the compound (D).

Abstract: A continuous process for the polymer-analogous reaction of polymers bearing functional groups with reactive compounds, wherein in a first step, a mixture is prepared from the polymers bearing functional groups and the reactive compounds, and in a second step, the mixture is conducted continuously through a reaction zone and brought to reaction there.

Abstract: A method of preparing an organosilicon compound comprising effecting a hydrosilylation reaction between (a) unsaturated compounds with terminal unsaturated groups and (b) silane compounds described by formula HSiR0mW3−m, where W is selected from the group consisting of C1 to C6 alkoxy groups, C6 to C10 aryloxy groups, and halogen atoms, R0 is an organic group, and m is 0, 1, or 2 in the presence of (c) a platinum catalyst and (d) an auxiliary catalyst selected from the group consisting of (1) silyl esters of acids derived from oxo acids of sulfur; (2) amide compounds having N—Si bonds; (3) urea compounds; (4) silyl esters of carbamic acid; (5) phosphoric acid compounds; and (6) cyclic compounds selected from the group consisting of (i) hydroxypyridine compounds, (ii) 8-hydroxyquinoline compounds, (iii) oxazolidinone compounds, and (iv) N-hydroxysuccinimide compounds.

Abstract: A polyalkoxysiloxane of the following rational formula: SiOa(OR)b(OH)c wherein R is a C1-4 alkyl group, a=0.86 to 1.30, b=2.18 to 1.30, and c≦0.10.

Abstract: An epoxy group-bearing organopolysiloxane or organosilane is prepared by effecting addition reaction between an organohydropolysiloxane or organohydrosilane and an alkenyl group-bearing epoxy compound in the presence of an addition reaction catalyst. A cyano group-bearing compound is co-present in the reaction system. The end organopolysiloxane or organosilane having a stabilized viscosity is obtained while avoiding gelation or thickening during reaction.

Abstract: An epoxysiloxane condensate is modified by means of an in situ reaction with an organic compound, which is di-functional or multifunctional if warranted. By means of the disclosed method, the characteristics of epoxysiloxane condensates, epoxy resin mixtures, epoxy resin formulations and molded bodies manufactured therefrom can be varied easily and economically.

Abstract: The present invention is directed to polymerizable dental compositions containing a) 3 to 80 wt. % of cycloaliphatic epoxides; b) 0 to 80 wt. % of an epoxide or a mixture of epoxides which are different from a); c) 3 to 85 wt. % of a filer material; d) 0.01 to 25 wt. % of initiators, inhibitors and/or accelerators; e) 0 to 25 wt. % of auxiliary agents, the individual percentages of which are in relation to the total weight. The new polymerizable agents are particularly suited as dental material.

Abstract: Radicicol derivatives represented by the following formula (I) having tyrosine kinase inhibition activity or pharmacologically acceptable salts thereof: wherein R1 and R2 are the same or different, and each represents hydrogen, alkanoyl, alkenoyl, tert-butyldiphenylsilyl or tert-butyldimethylsilyl; R3 represents Y—R5 {wherein Y represents substituted or unsubstituted alkylene; and R5 represents CONR6R7 (wherein R6 represents hydrogen, hydroxyl, substituted or unsubstituted lower alkyl, substituted or unsubstituted higher alkyl; R7 represents hydroxyl, substituted lower alkyl), CO2R12 (wherein R12 represents substituted lower alkyl, substituted or unsubstituted higher alkyl, X represents halogen.

Abstract: The present invention relates to surface-modified fillers obtained by mixing a filler with water, adding an water-based organosiloxane composition with very thorough mixing, wherein the organosiloxanes are soluble in water and contain, in addition to OH groups, at least one amino-functional group and optionally a functional group from the series consisting of alkyl, haloalkyl, alkenyl, glycidyl ether alkyl, acryloxyalkyl and methacryloxyalkyl, and wherein a functional group is bonded to each silicon atom of the organosiloxane, and drying the mixture. The present invention also provides a process for the surface modification of fillers, their use and ethylene-vinyl acetate copolymer compositions which include the surface-modified fillers.

Abstract: A thermosetting resin composition obtained by heat treating, under the specified conditions, a mixture of a polyaddition thermosetting resin, a silicic compound (oligomer) having a functional group capable of causing an addition reaction with a curing agent for the polyaddition thermosetting resin, and water, followed by adding of a curing agent for the polyaddition thermosetting resin is useful for producing thermosetting resin molded articles, resin encapsulated semiconductor devices, automobile parts, etc., which are high in heat resistance, small in change of elastic modulus at high temperatures, and resistant to crack and peeling.

Abstract: A curable organopolysiloxane composition that can form a cured product that is strongly adhesive to substrates such as glasses, plastics, and metals and exhibits a very durable adhesion in which adhesiveness is maintained even under severe conditions such as immersion in hot water. The curable organopolysiloxane composition comprises from 1 to 75 weight % of a calcium carbonate powder whose surface has been treated with both (a) a rosin or a rosin derivative and (b) a fatty acid or a fatty acid derivative.

Abstract: A method is provided for preparing high purity organofunctional alkyldialkoxysilanes by reacting hydroalkyldialkoxysilanes with olefins wherein formation of undesired close-boiling by-products by an alkyl/alkoxy group exchange reaction is minimized.

Abstract: An epoxy resin composition comprising (A) a biphenyl skeleton-bearing epoxy resin, (B) a biphenyl skeleton-bearing phenolic resin as a curing agent, (C) an organosiloxane containing phenyl and organooxy groups, and (D) an inorganic filler is suited for semiconductor encapsulation since it is effectively moldable and cures into a part having improved reflow crack resistance, moisture resistance, and flame retardance. It does not pose a hazard to human health or the environment.

Abstract: A photocationically curable composition and a process for producing the same are provided. The composition comprises, as the essential component, a condensation product having an oxetanyl group, which is a condensation product of a hydrolyzate of an organic silane compound having an oxetanyl group and being represented by the formula below, or of a mixture of said organic silane compound and a reactive silicone having a siloxane linkage-forming group: ##STR1## wherein R.sup.0 means an organic functional group having an oxetanyl group, and X means a hydrolyzable group. The composition forms cured coating films of high surface hardness, and is useful as hard coating agents.

Abstract: A method for synthesizing organosilicon compounds that contain a functional group bonded to silicon across the Si--C bond. The method comprises reacting an unsaturated group-functional organic compound or unsaturated group-functional organosilicon compound with a hydro(hydrocarbonoxy)silane compound, where the reaction is carried out in the presence of a platinum catalyst.

Abstract: A process for preparing 4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketones of the general formula I, in particular of the (1R,4S)-4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketone of the formula Ia ##STR1## which is required for preparing the red dye capsorubin which is in demand, starts from 2,2,6-trimethylcyclohexanones of the general formula II ##STR2## where R is hydrogen or a protective group, via the novel intermediates of the general formulae V and VI ##STR3## by diastereoselective epoxidation and reaction of the resulting 7-oxabicyclo[4.1.0]heptanes of the general formula VIII ##STR4## with Lewis acids and, where appropriate, removal of the protective group. Also claimed are the novel intermediates of the formula V and their (1S) and (1R) isomers and those of the formula VIII as well as their (1R,3S,6S), (1S,3S,6R) and (1R,3R,6S) isomers.