A Potentially Divergent and Rapid Route to Analogues of Deoxycyclitols, Pentopyranoses, 6-Deoxyhexoses, and Hexoses
摘要:
Direct precursors to analogues of pentopyranoses, 6-deoxyhexoses, and hexoses, in which a CF2 center replaces the pyranose oxygen, have been synthesized rapidly from trifluoroethanol. A simple scaleable allylation reaction delivers ethers which undergo dehydrofluorination/metalation, followed by addition to either acrolein or cinnamaldehyde, to afford allylic alcohols. Fluorine-assisted [3,3]-rearrangement followed by reduction with sodium borohydride delivers diols, which undergo RCM smoothly to afford cyclohexene diols.
A Potentially Divergent and Rapid Route to Analogues of Deoxycyclitols, Pentopyranoses, 6-Deoxyhexoses, and Hexoses
摘要:
Direct precursors to analogues of pentopyranoses, 6-deoxyhexoses, and hexoses, in which a CF2 center replaces the pyranose oxygen, have been synthesized rapidly from trifluoroethanol. A simple scaleable allylation reaction delivers ethers which undergo dehydrofluorination/metalation, followed by addition to either acrolein or cinnamaldehyde, to afford allylic alcohols. Fluorine-assisted [3,3]-rearrangement followed by reduction with sodium borohydride delivers diols, which undergo RCM smoothly to afford cyclohexene diols.
A direct and rapid route to α,α-difluoroacylsilanes from trifluoroethanol
作者:Christophe Audouard、Maxime R. Garayt、Erwan Kérourédan、Jonathan M. Percy、Hongli Yang
DOI:10.1016/j.jfluchem.2005.01.005
日期:2005.4
α-Difluoroacylsilanes were synthesised directly from a range of allyl ethers of trifluoroethanol via dehydrofluorination/metallation procedures, followed by thermal [3,3]-sigmatropic rearrangement of the intermediate vinylmetals. The scope and limitations of ether synthesis and dehydrofluorination/metallation are described.
Allyl ethers of trifluoroethanol are transformed to difluorinated analogues of deoxysugars via concise sequences involving dehydrofluorination/metallation, [3,3]-Claisen rearrangement, reduction, and RCM, affording cyclohexenediol substrates for dihydroxylation reactions.