Abstract: Disclosed is a process for the coupling of a Grignard reagent RMgX with an allylic halide in the presence of a dipolar aprotic solvent wherein the improvement, for obtaining improved yield and selectivity, comprises adding a catalyst to said Grignard or allylic halide and then carrying out the coupling reaction by the addition of the Grignard reagent to the allylic halide, said reaction being characterized by the displacement at the gamma position (relative to the halide) of the allylic halide with R of the Grignard reagent, migration of the allylic double bond in the direction of the halogen atom and loss of halogen. The present invention also resides in the discovery of certain novel procedures for the synthesis of Vitamin E. Specific embodiments of this aspect of the invention reside in the syntheses of 6,7-dehydrophytol, 10,11-dihydrofarnesene, phytone, hexahydropseudoionone, and related compounds as precursors for Vitamin E.
Abstract: A process for the preparation of bromoalkyl esters and vicinal glycol esters which comprises thermally decomposing at temperatures of from 100.degree. C. to 200.degree. C. a bis(2-bromoalkyl)tellurium dicarboxylate compound of the formula ##STR1## wherein at least one R is hydrogen or R is a methyl group and R' is hydrogen or an alkyl group having 1 to 3 carbon atoms in the presence of an aliphatic monocarboxylic acid selected from formic, acetic, propionic or butyric acid employed as solvent and to facilitate solvolysis in the reaction to give in addition to the bromoalkyl ester, the vicinal glycol ester. An inert acetonitrile solvent may be employed alone to give predominately the bromoalkyl ester or an admixture with the acid may be employed. Oxygen is preferably employed with the carboxylic acid solvent to provide an increase in the mole ratio of vicinal glycol ester to the bromoalkyl ester produced.
Abstract: A process for the preparation of 2-bromoalkyl esters and vicinal glycol esters which comprises thermally decomposing at temperatures of from 100.degree. C. to 200.degree. C. an organic bromoalkyl tellurium compound selected from 2-bromoalkyltellurium tribromide or bis(2-bromoalkyl)tellurium dibromide, wherein the alkyl group is ethyl, propyl or butyl, in a carboxylic acid having from 1 to 4 carbon atoms which is employed as solvent as well as to supply the ester moiety to the esters produced. The esters may be converted to the respective glycol with water or an aqueous base.
Abstract: Disclosed is a process for the coupling of a Grignard reagent RMgX with an allylic halide in the presence of a dipolar aprotic solvent wherein the improvement, for obtaining improved yield and selectivity, comprises adding a catalyst to said Grignard or allylic halide and then carrying out the coupling reaction by the addition of the Grignard reagent to the allylic halide, said reaction being characterized by the displacement at the gamma position (relative to the halide) of the allylic halide with R of the Grignard reagent, migration of the allylic double bond in the direction of the halogen atom and loss of halogen. The present invention also resides in the discovery of certain novel procedures for the synthesis of Vitamin E. Specific embodiments of this aspect of the invention reside in the syntheses of 6,7-dehydrophytol, 10,11-dihydrofarnesene, phytone, hexahydropseudoionone, and related compounds as precursors for Vitamin E.
Abstract: New dehydrotocopherols, namely cis- and trans- 3',4'-dehydrotocopherol; cis- and trans- 4',5'-dehydrotocopherol; and 4',4'-a-dehydrotocopherol, and new didehydrotocopherols, namely cis- and trans- 3',4'-11',12'-didehydrotocopherol; cis- and trans- 4',5'-11',12'-didehydrotocopherol; and 4',4'a-11',12'-didehydrotocopherol, are useful intermediates in the preparation of Vitamin E.These intermediates are prepared by reacting trimethylhydroquinone under acid catalysis with certain C.sub.20 intermediates, namely: ##STR1## where R represnts a 3,7-dimethyloctyl or a 3,7-dimethyl-6-octenyl radical and X is halogen, hydroxyl, acetate, C.sub.1-4 alkanoate, C.sub.3-4 alkenoate, aralkenoate and benzoate.