Synthesis of α-Keto-Imides via Oxidation of Ynamides
作者:Ziyad F. Al-Rashid、Whitney L. Johnson、Richard P. Hsung、Yonggang Wei、Pei-Yuan Yao、Renhei Liu、Kang Zhao
DOI:10.1021/jo8015067
日期:2008.11.21
A de novo preparation of alpha-keto-imides via ynamide oxidation is described. With a number of alkyne oxidation conditions screened, a highly efficient RuO2-NaIO4 mediated oxidation and a DMDO oxidation have been identified to tolerate a wide range of ynamide types. In addition to accessing a wide variety of a-keto-imides, the RuO2-NaIO4 protocol provides a novel entry to the vicinal tricarboryl motif via oxidation of push-pull ynamides, and imido acylsilanes from silyl-substituted ynamides. Chemoselective oxidation of ynamides containing olefins can be achieved by using DMDO, while the RuO2-NaIO4 protocol is not effective. These studies provide further support for the synthetic utility of ynamides.
An Asymmetric Vinylogous Michael Cascade of Silyl Glyoximide, Vinyl Grignard, and Nitroalkenes via Long Range Stereoinduction
作者:Gregory R. Boyce、Jeffrey S. Johnson
DOI:10.1021/acs.joc.5b02693
日期:2016.2.19
A diastereoselective auxiliary-mediated vinylation/[1,2]-Brook rearrangement/vinylogous Michael cascade of silyl glyoximide, vinylmagnesium bromide, and nitroalkenes is described. The reaction occurs with complete regio- and diastereocontrol in good yield. The diastereoselectivity is induced by a rare instance of 1,7-chirality transfer that is hypothesized to arise from a trans-multihetero-decalin
Three-Component Coupling Reactions of Silyl Glyoxylates, Vinyl Grignard Reagent, and Nitroalkenes: An Efficient, Highly Diastereoselective Approach to Nitrocyclopentanols
作者:Gregory R. Boyce、Jeffrey S. Johnson
DOI:10.1002/anie.201003470
日期:2010.11.15
easy: A regio‐ and stereoselective three‐component couplingreaction generates functionalized (Z)‐silyl enol ethers through a vinylation/[1,2]‐Brook rearrangement/vinylogous Michael reaction cascade. These adducts can then undergo a diastereoselective deprotection/intramolecular Henry sequence to rapidly assemble densely functionalized nitrocyclopentanols with three contiguous stereocenters (see scheme;
快速简便:区域选择性和立体选择性三组分偶联反应通过乙烯基化/[1,2]-布鲁克重排/乙烯基迈克尔反应级联反应生成官能化的 ( Z )-甲硅烷基烯醇醚。然后,这些加合物可以进行非对映选择性脱保护/分子内亨利序列,以快速组装具有三个连续立体中心的密集官能化硝基环戊醇(参见方案;TES=三乙基甲硅烷基)。