Catalytic Asymmetric Addition of Meldrum’s Acid, Malononitrile, and 1,3-Dicarbonyls to<i>ortho</i>-Quinone Methides Generated In Situ Under Basic Conditions
作者:Lorenzo Caruana、Martina Mondatori、Vasco Corti、Sara Morales、Andrea Mazzanti、Mariafrancesca Fochi、Luca Bernardi
DOI:10.1002/chem.201500710
日期:2015.4.13
unstable ortho‐quinone methides (o‐QMs) in catalytic asymmetric settings is presented. The enantioselective reactions are catalysed by bifunctional organocatalysts, and the o‐QM intermediates are formed in situ from 2‐sulfonylalkyl phenols through base‐promoted elimination of sulfinic acid. The use of mild Brønsted basic conditions for transiently generating o‐QMs in catalytic asymmetric processes is unprecedented
提出了一种在催化不对称环境中利用高反应性和不稳定的邻醌甲基甲烷(o- QMs)的新方法。对映选择性反应由双功能有机催化剂催化,o- QM中间体是由2-磺酰基烷基苯酚通过碱促进的亚磺酸消除而原位形成的。在催化不对称过程中短暂使用温和的布朗斯台德基本条件来瞬时生成o- QMs是前所未有的,它可以有效地参与亲核试剂如Meldrum的酸,丙二腈和1,3-二羰基的反应。催化转化为3,4-二氢香豆素,4 H提供了新的通用条目色烯和黄嘌呤酮。这些框架是天然产物和药物化学中的重复结构,这是由催化加合物形式的(R)-托特罗定和(S)-4-甲氧基金刚烷酸酯的正式合成所证明的。