Abstract: A method for the preparation of 1-chloro-1,2,2,2-tetrafluoroethane which comprises treating 1,1-dichloro-1,2,2,2-tetrafluoroethane, optionally in the form of an isomer mixture, with an alkali metal amalgam in an active hydrogen containing liquid medium which includes a solvent for the dichlorotetrafluoroethane.

Abstract: Chiral Schiff bases according to the general formula: ##STR1## and transition metal complexes thereof, wherein C.sup.* is an asymmetric carbon atom, R.sup.1 and R.sup.2, which may be the same or different are alkyl, aralkyl, aryl or alkaryl, R.sup.3 is hydrogen, alkyl, aralkyl, aryl or alkaryl, R.sup.4 and R.sup.5, which may be the same or different, are hydrogen or lower alkyl or, where n is 1, may with the cyclic ring to which CR.sup.4 R.sup.

Abstract: 3-(Halogenovinyl- or propenyl-)-2,2-dimethyl cyclopropane-1-carboxylic acid esters, which are precursors of, or may themselves be, pyrethroid insecticides, are prepared by the reaction of certain halogenopentadienes with an alkyl diazoacetate in the presence of a catalyst which is a transition metal complex of certain chiral Schiff bases, which catalysts tend to increase the yield of preferred cis IR isomer relative to the other possible isomers.

Abstract: Chiral Schiff bases, and transition metal complexes thereof, of formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3, which may be the same ordifferent, are hydrogen, alkyl, aralkyl, aryl, alkaryl, a substituent containing a hetero atom, or two of R.sup.1, R.sup.2 and R.sup.3 together with the pyridine ring from fused system, R.sup.4 and R.sup.5 which may be the same or different, are hydrogen, lower alkyl, or, where n is 1, may with the pyridine ring to which CR.sup.4 R.sup.5 is attached form a fused system, R.sup.6 is hydrogen, alkyl, aralkyl, aryl or alkaryl, n is 0, 1 or 2 and J and K, which may be the same or different, are groups of the formulae: ##STR2## in which C* is an asymmetric carbon atom, and R.sup.7 and R.sup.8, which may be the same or different, are alkyl, aralkyl, aryl or alkaryl, or ##STR3## in which at least the ring carbon atom to which the iminyl nitrogen atom is attached is asymmetric, at least one of the carbon atoms adjacent the said ring carbon atom bears a hydroxyl group, R.sup.

Abstract: 3-Halogenoethyl- or propyl-2,2-dimethylcyclopropane carboxylic acid esters, which are intermediates in the preparation of synthetic pyrethroids, are prepared by the reaction of certain halogenopentenes or hexenes with a diazoacetic ester in the presence of a catalyst which is metallic copper or a copper (II) salt, a rhodium (II) salt of a carboxylic acid or a transition metal complex of certain chiral Schiff bases. By the use of the latter class of catalysts the yield of preferred cis IR isomer may be increased relative to the other possible isomers.