General Allylic C–H Alkylation with Tertiary Nucleophiles
作者:Jennifer M. Howell、Wei Liu、Andrew J. Young、M. Christina White
DOI:10.1021/ja500726e
日期:2014.4.16
A general method for intermolecular allylic C–H alkylation of terminal olefins with tertiary nucleophiles has been accomplished employing palladium(II)/bis(sulfoxide) catalysis. Allylic C–H alkylation furnishes products in good yields (avg. 64%) with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E:Z). For the first time, the olefin scope encompasses unactivated aliphatic olefins
Transition-metal-free α-arylation of α-nitroketones with diaryliodonium salts has been realized for the first time. As an application of this methodology, a concise synthesis of the clinical drug tiletamine was also achieved via a three-step procedure from 2-nitrocyclohexanone without the isolation of intermediates.
Organocatalytic Asymmetric Conjugate Addition and Cascade Acyl Transfer Reaction of α-Nitroketones
作者:Rui-jiong Lu、Yun-yun Yan、Jin-jia Wang、Quan-sheng Du、Shao-zhen Nie、Ming Yan
DOI:10.1021/jo2009752
日期:2011.8.5
Organocatalytic asymmetric conjugate addition of α-nitroketones to β,γ-unsaturated α-keto esters has been developed. A pyrrolidine-based thiourea–tertiary amine was identified as the best catalyst. The reaction was found to proceed via cascade conjugate addition and acyl transfer reaction. A number of α-nitroketones and β,γ-unsaturated α-keto esters were examined in this transformation. 5-Nitro-2-