Although the [2,3]-Wittig and Wittig-Still rearrangements have long been known, their application in the generation of quaternary carbon centers in carbocyclic ring systems is sparse. Model studies utilizing this strategy and possible mechanisms are discussed herein. Unprecedented examples of an a-elimination pathway from stannylmethyl allyl ethers as a major undesired product in some Wittig-Still rearrangements are reported.
Reductive and Regioselective Cleavage of Oxetanes Assisted by the Neighboring Hydroxyl
作者:Michiharu Kato、Haruo Kitahara、Akira Yoshikoshi
DOI:10.1246/bcsj.59.1647
日期:1986.5
aluminium hydride, 1,6-dioxadispiro[2.0.3.4]undecane and 5-methl-2-oxaspiro[3.5]nonan-5-ol gave 1,2-dimethyl-c-2-(hydroxymethyl)-r-1-cyclohexanol (5) which was produced from regioselective C–O bond cleavage of oxetane rings by an intramolecular attack of hydride. The stereochemistry of 5 was confirmed by an unambiguous synthesis based on the Sharpless oxidation of 1-methyl-2-methylenecyclohexanemethanol.