hydrobromination of terminal and internal alkynes with a commercially available solution of hydrogen bromide in acetic acid has been investigated for regio- and stereoselectivesynthesis of bromoalkenes. Under an aerobic atmosphere at room temperature, the reaction of ethynylarenes with a small excess of HBr efficiently gave (2-bromoethenyl)arenes with good to high E-selectivity. (Alk-1-ynyl)arenes, or internal
Stereo- and regioselective formation of silyl enol ethers via oxidation of vinyl anions
作者:Franklin A. Davis、G. Sankar Lal、Jia Wei
DOI:10.1016/s0040-4039(00)80471-2
日期:1988.1
Oxidation of E- and Z-vinyl lithiums with silyl peroxides 5 affords silyl enolethers 3 in good to excellent yield with retention of configuration. This methodology represents a useful new procedure for the stereo- and regioselective synthesis of ketone enolates.