study, stereoselective conjugate addition of ketones to alkylidenemalonates using organocatalyst has been developed. The reaction in the presence of 20 mol% of a novel thiourea‐sulfonamide organocatalyst afforded conjugate adducts in moderate to high yields (up to 81%) under mild reaction conditions. Excellent diastereoselectivity (up to 98:2 dr) and enantioselectivity (up to 88% ee) were achieved.
Enantioselective Organocatalytic Michael Addition of Ketones to Alkylidene Malonates
作者:Siang-En Syu、Chan-Hui Huang、Ko-Wei Chen、Chia-Jui Lee、Utpal Das、Yeong-Jiunn Jang、Wenwei Lin
DOI:10.1002/chir.22055
日期:2012.8
studied for the direct asymmetric Michaeladdition of ketones and alkylidenemalonates. The organocatalyst (S)‐2‐((naphthalen‐2‐ylthio)methyl)pyrrolidine, bearing a pyrrolidine and a sulfide moiety, showed a very high catalytic activity in the absence of additives. The reaction condition is mild, and the Michael adducts were obtained in very good enantioselectivities (up to 96%), diastereoselectivities
Highly Enantioselective Conjugate Addition of Ketones to Alkylidene Malonates Catalyzed by a Pyrrolidinyl-Camphor-Derived Organocatalyst
作者:Dhananjay R. Magar、Chihliang Chang、Ying-Fang Ting、Kwunmin Chen
DOI:10.1002/ejoc.201000072
日期:2010.4
Pyrrolidinyl-camphor derivatives have been proven to be efficient organocatalysts for enantioselective conjugate addition of ketones to alkylidenemalonates, affording high chemical yields (up to 95 %) of the corresponding products with high to excellent levels of diastereoselectivity (up to >99:1 dr) and enantioselectivity (up to 96 % ee) under solvent-free reaction conditions at ambient temperature.
吡咯烷基-樟脑衍生物已被证明是酮与亚烷基丙二酸酯的对映选择性共轭加成的有效有机催化剂,可提供高化学产率(高达 95%)的相应产物,并具有高至极好的非对映选择性(高达 >99:1 dr ) 和对映选择性(高达 96% ee),在无溶剂反应条件下,室温。
Asymmetric Michael Addition of Ketones to Alkylidene Malonates and Allylidene Malonates via Enamine–Metal Lewis Acid Bifunctional Catalysis
作者:Lu Liu、Ryan Sarkisian、Zhenghu Xu、Hong Wang
DOI:10.1021/jo301070s
日期:2012.9.7
Novel enamine–metal Lewis acid bifunctional catalysts were successfully applied to the asymmetric Michaeladdition of ketones to alkylidenemalonates, offering excellent stereoselectivity (up to >99% ee and >99:1 dr). The asymmetric Michaeladdition of ketones to allylidene malonates was also achieved.