Subject wittig chemistry

The Pirrung synthesis is notable for its brevity and clever amalgamation of [2 + 2] photocycloaddition and Wagner-Meerwein rearrangement chemistry Enol ether 757 was reacted with the Grignard rea nt from 5-bromo-2-methyl-l-pentene, subjected to acid hydrolysis, and irradiated to generate the tricycle 738. Wittig olefination of this ketone and treatment with p-toluenesulfonic acid provided racemic isocomene. 

The study of the chemistry of acyl groups other than formyl is much less developed. Acetyltetrathiafulvalene (63) has been subjected to crossed aldol condensations with acetylferrocene and (acetophenone) Cr(CO)3 [92JOM(429)335]. Some Wittig reactions of 63 have been reported (93TL7475), as well as a few reactions of ketone 64 (90CC816) (Scheme 27). 

Phosphorus.- As in previous years the chemistry of the Wittig reaction and related processes has been the subject of a large proportion of the publications in this area. Various stereochemical aspects of the Wittig reaction have been described, a-Oxygenated cyclohexanones and 2,3-epoxycyclohexane react with Ph2P=CHMe to give the -ethylidene derivatives in a highly stereoselective fashion (Scheme 55) under both Li-base and Li-free con-... 

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