[2,3]-Wittig rearrangement of allylic glycolate esters via boron and tin enolates
摘要:
Wittig rearrangement of allylic glycolate esters via boron and tin enolates gave diastereoselectivities as high as 99.5 : 0.5. Tin enolates were more stereoselective than boron enolates.
[3,3]-Sigmatropic rearrangement of silyl ketene acetals of methyl α-(allyloxy) acetates.
作者:Stanley Raucher、Linda M Gustavson
DOI:10.1016/s0040-4039(00)84311-7
日期:1986.1
Although the lithium enolate undergoes [2,3]-sigmatropic rearrangement to give , the silylketeneacetals undergo [3,3]-sigmatropic rearrangement to give . This is the first reported [3,3]-sigmatropic rearrangement of a 1,1-dioxy-3-oxa-1,5-diene.
A novel silyl triflate-mediated [2,3]sigmatropicrearrangement of (allyloxy)acetates and their ketene silyl acetals is described, which is proposed to proceed via rarely precedented oxygen ylides. The formal [2,3]Wittlg shift is characterized by the unique stereoselectivity, , the rarely precedented -selectivity and the high erythro-selectivity.
Enantioselective [2,3]Wittig rearrangement involving a chiral boron enolate terminus
作者:Katsuhiko Fujimoto、Takeshi Nakai
DOI:10.1016/s0040-4039(00)73309-0
日期:1994.7
The first enantioselective version of the ester enolate [2,3]Wittigrearrangement is described which involves a chiral boron enolate with a chiral bis-sulfonamide ligand to provide a high enantioselectivity(>95%ee), along with a high threo diastereoselectivity.