Carboxylic Acids as A Traceless Activation Group for Conjugate Additions: A Three-Step Synthesis of (±)-Pregabalin
作者:Lingling Chu、Chisa Ohta、Zhiwei Zuo、David W. C. MacMillan
DOI:10.1021/ja505964r
日期:2014.8.6
carboxylic acids as a traceless activation group for radical Michael additions has been accomplished via visible light-mediated photoredox catalysis. Photon-induced oxidation of a broad series of carboxylic acids, including hydrocarbon-substituted, α-oxy, and α-amino acids, provides a versatile CO2-extrusion platform to generate Michael donors without the requirement for organometallic activation or propagation
羧酸作为自由基迈克尔加成的无痕活化基团的直接应用是通过可见光介导的光氧化还原催化实现的。光子诱导氧化一系列广泛的羧酸,包括碳氢化合物取代的、α-氧基和 α-氨基酸,提供了一个多功能的 CO2 挤出平台来生成迈克尔供体,而无需有机金属活化或传播。多种迈克尔受体适用于这种新的共轭加成策略。还介绍了该技术在药物普瑞巴林(由辉瑞以商品名 Lyrica 商业化)的三步合成中的应用。
A Desulfurative Strategy for the Generation of Alkyl Radicals Enabled by Visible‐Light Photoredox Catalysis
a new desulfurative method for generating primary, secondary, and tertiary alkyl radicals through visible‐light photoredoxcatalysis. A process that involves the generation of N‐centered radicalsfrom sulfinamide intermediates, followed by subsequent fragmentation, is critical to forming the corresponding alkyl radical species. This strategy has been successfully applied to conjugate addition reactions
Metal-Free Hydrogenation of Electron-Poor Allenes and Alkenes
作者:Blanca Inés、David Palomas、Sigrid Holle、Sebastian Steinberg、Juan A. Nicasio、Manuel Alcarazo
DOI:10.1002/anie.201205348
日期:2012.12.3
The poorer, the better: A metal‐free catalytic procedure for the reduction of electron‐poor allenes and alkenes has been developed. The method employs a frustrated Lewis pair based catalyst. 1,4‐Diazabicyclo[2.2.2]octane (DABCO)/B(C6F5)3 was shown to be the best combination in optimization studies.
越差越好:已开发出一种用于减少电子贫乏的烯和烯烃的无金属催化方法。该方法使用沮丧的路易斯对基催化剂。1,4-二氮杂双环[2.2.2]辛烷(DABCO)/ B(C 6 F 5)3被证明是优化研究的最佳组合。
A Convenient Synthesis of the (<i>E</i>)-Monoacetates of 2-Alkylidenepropane-1,3-diols
Various kinds of 3-substituted (E)-2-(hydroxymethyl)prop-2-enyl acetates were conveniently obtained in excellent yields by the regiospecific acetylation of 2-alkylidenepropane-1,3-diols with 10 equivalents of vinyl acetate in the presence of 50% w/w porcine pancreatic lipase (PPL) type II; the starting materials or (Z)-monoacetate or diacetate byproducts were generally not present.
Catalytic Asymmetric Conjugate Addition of a Borylalkyl Copper Complex for Chiral Organoboronate Synthesis
作者:Won Jun Jang、Jaesook Yun
DOI:10.1002/anie.201909712
日期:2019.12.9
We report the catalytic enantioselectiveconjugateaddition of a borylalkyl copper nucleophile generated in situ from a 1,1-diborylmethane derivative to α,β-unsaturated diesters. In the presence of a chiral N-heterocyclic carbene (NHC)-copper catalyst, this method facilitated the enantioselective incorporation of a CH2 Bpin moiety at the β-position of the diesters to yield β-chiral alkyl boronates