195518-76-4Relevant academic research and scientific papers
Synthesis of α-hydroxy-β,β-difluoro-γ-ketoesters via [3,3]sigmatropic rearrangements
Broadhurst, Michael J.,Brown, Samantha J.,Percy, Jonathan M.,Prime, Michael E.
, p. 3217 - 3226 (2007/10/03)
Readily available γ,γ-difluorinated allylic alcohols obtained from trifluoroethanol were esterified efficiently. Exposure to strong base (LDA) afforded the ester enolates, in which chelation both controlled configuration and stabilised against fragmentation, which were trapped as their silyl ketene acetals. Rearrangement occurred to afford base-sensitive acid products. Esterification under mild conditions afforded the purifiable methyl esters in which the masked ketone had been released. Educts with either a benzyloxy or an allyloxy group at the α-position could be deprotected releasing the alcohols. The Royal Society of Chemistry 2000.
Chelated [3,3]-rearrangements of difluoroallylic alcohols
Broadhurst,Percy,Prime
, p. 5903 - 5906 (2007/10/03)
Whereas the lithium enolates of acetate and propionate esters of difluoroallylic alcohols fragment rapidly, even at -78*C, methoxy- and benzyloxy-acetates form chelated enolates which undergo smooth [3,3]-rearrangement as their silyl ketene acetals. The latent ketone function can be revealed under mild conditions CMeOH,SOCl2) to afford very highly functionalised CF2 compounds.
