Chiral ammonium betaines:: A bifunctional organic base catalyst for asymmetric Mannich-type reaction of α-nitrocarboxylates
Chiral ammonium betaines:: A bifunctional organic base catalyst for asymmetric Mannich-type reaction of α-nitrocarboxylates
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DOI：
10.1021/ja8041004
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发表时间：
2008-08-20
影响因子：
15
通讯作者：
Ooi, Takashi
中科院分区：
文献类型：
--
作者：
Uraguchi, Daisuke;Koshimoto, Kyohei;Ooi, Takashi
手性甜菜碱铵是一种分子内离子对季芳基氧化铵3，它作为一种对映选择性有机碱催化剂的巨大潜力已经成功地在取代的硝基羧酸酯2与各种N-Boc亚胺1的高度对映选择性直接mannich型反应中得到了证明。本研究为双功能手性季铵盐的设计及其作为均相有机分子催化剂的应用提供了新的思路。
A chiral ammonium betaine, an intramolecular ion-pairing quaternary ammonium aryloxide 3, has been designed and its vast potential as an enantioselective organic base catalyst has been successfully demonstrated in the highly enantioselective direct Mannich-type reaction of alpha-substituted alpha-nitrocarboxylates 2 with various N-Boc imines 1. The present study provides a conceptually new approach toward the design of bifunctional, chiral quaternary ammonium salts and their utilizations as a homogeneous organic molecular catalyst.