Felkin−Anh Stereoselectivity in Cycloadditions of Acetylketene: Evidence for a Concerted, Pseudopericyclic Pathway
作者:William Shumway、Sihyun Ham、Jessica Moer、Bruce R. Whittlesey、David M. Birney
DOI:10.1021/jo0002644
日期:2000.11.1
The cycloadditions of acetylketene with alpha-chiral aldehydes and ketones are shown to be diastereoselective, forming a tertiary or quaternary chiral center at an acetal or ketal carbon with good stereocontrol. X-ray crystallography of a minor product (5b) shows that the major products (e.g., 4b) are those predicted by the Felkin-Anh model. Transition states are reported at the MP2/6-31G level for