Ynolates were found to react with alpha-alkoxy-, alpha-siloxy-, and alpha-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the beta-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z
Highly Diastereoselective Chelation-Controlled Additions to α-Silyloxy Ketones
作者:Gretchen R. Stanton、Gamze Koz、Patrick J. Walsh
DOI:10.1021/ja201629d
日期:2011.5.25
predict that the addition of organometallic reagents to silyl-protected α-hydroxy ketones proceeds via a nonchelation pathway to give anti-diol addition products. This prediction has held true for the vast majority of additions reported in the literature, and few methods for chelation-controlled additions of organometallic reagents to silyl-protected α-hydroxy ketones have been introduced. Herein, we present
作者:Pengfei Hu、Byron K. Peters、Christian A. Malapit、Julien C. Vantourout、Pan Wang、Jinjun Li、Lucas Mele、Pierre-Georges Echeverria、Shelley D. Minteer、Phil S. Baran
DOI:10.1021/jacs.0c11214
日期:2020.12.16
A user-friendly approach is presented to sidestep the venerable Grignard addition to unactivated ketones to access tertiary alcohols by reversing the polarity of the disconnection. In this work a ketone instead acts as a nucleophile when adding to simpleunactivatedolefins to accomplish the same overall transformation. The scope of this coupling is broad as enabled using an electrochemical approach
Provided is a novel compound represented by the following formula
Wherein each symbol is as defined in the specification, or a salt thereof, which has an angiotensin II receptor antagonistic activity and a peroxisome proliferator-activated receptor γ agonistic activity, and is useful as an agent for the prophylaxis or treatment of circulatory diseases such as hypertension and the like and/or metabolic diseases such as diabetes and the like, and the like.
some (E)- and (Z)-2-fluoroalk-2-enoates prepared from the corresponding 2-hydroxycarbonyl compounds and ethyl 2-(diethoxyphosphoryl)-2-fluoroacetate have been transformed in high conversions into the target 3-fluorofuran-2(5H)-ones by an efficient Z/E photoisomerisation of noncyclisable Z isomers followed by acid-catalysed cyclisation. In contrast, the acid-catalysed deprotection of ethyl (E)- and