Enantioselective Construction of a 2,8-Dioxabicyclo[3.2.1]octane Ring System via [2,3]-Sigmatropic Rearrangement of Oxonium Ylide Using Chiral Dirhodium(II) Carboxylates
作者:Naoyuki Shimada、Seiichi Nakamura、Masahiro Anada、Motoo Shiro、Shunichi Hashimoto
DOI:10.1246/cl.2009.488
日期:2009.5.5
Dirhodium(II) tetrakis[N-tetrafluorophthaloyl-(S)-tert-leucinate], Rh2(S-TFPTTL)4, is an exceptionally efficient catalyst for enantioselective tandem cyclic oxonium ylide formation and [2,3]-sigmatropic rearrangement from α-diazo-β-ketoester bearing cyclic allylic acetal functionality, providing the 2,8-dioxabicyclo[3.2.1]octane core structure of zaragozic acids in up to 93% ee.
二铑(II)四(N-四氟邻苯二甲酰基-(S)-四氟离子酸),Rh2(S-TFPTTL)4,是一种异常高效的催化剂,用于从具有环状烯丙基缩醛功能的α-二氮-β-酮酯中进行enantioselective双重环氧阳离子形成和[2,3]-σ-转位,为扎拉哥兹酸提供了高达93% ee的2,8-二氧双环[3.2.1]辛烷核心结构。