Asymmetric Aza-Morita-Baylis-Hillman-Type Reactions: The Highly Enantioselective Reaction between Unmodified α,β- Unsaturated Aldehydes and N-Acylimines by Organo-co-catalysis
作者:Sylva Číhalová、Pawel Dziedzic、Armando Córdova、Jan Veselý
DOI:10.1002/adsc.201000951
日期:2011.5.9
(MBH)‐type reaction between N‐carbamate‐protected imines and α,β‐unsaturated aldehydes has been developed. The organic co‐catalytic system of proline and 1,4‐diazabicyclo[2.2.2]octane (DABCO) enables the asymmetric synthesis of the corresponding N‐Boc‐ and N‐Cbz‐protected β‐amino‐α‐alkylidene‐aldehydes in good to high yields and up to 99% ee. In the case of aza‐MBH‐type addition of enals to phenylprop‐2‐ene‐1‐imines
高对映选择性的有机助催化氮杂森田-的Baylis-希尔曼(MBH)型之间的反应ñ -氨基甲酸酯保护的亚胺和α,β不饱和醛已经研制成功。脯氨酸和1,4-二氮杂双环[2.2.2]辛烷(DABCO)的有机共催化体系可实现不对称合成相应的N - Boc-和N -Cbz保护的β-氨基-α-亚烷基-醛良品率高,ee高达99%。在苯丙-2-烯-1-亚胺的氮杂-MBH型加成反应中,助催化反应具有出色的1,2-选择性。有机-共催化的氮杂-MBH型反应也可以通过将α,β-不饱和醛直接高度对映选择性地添加到稳定的氮中来进行用氨基甲酸酯保护的α-酰胺基砜可得到相应的β-氨基-α-亚烷基醛,ee最高可达99%。有机-共催化的氮杂-MBH型反应也是近对映体纯的β-氨基-α-亚烷基-氨基酸和β-氨基-α-亚烷基-内酰胺(99%ee)的快速入口。还讨论了手性胺和DABCO共催化的aza-MBH型反应的机理和立体化学。