ACYCLIC STEREOSELECTION .47. STEREOCHEMISTRY OF THE MICHAEL ADDITION OF ESTER AND KETONE ENOLATES TO ALPHA,BETA-UNSATURATED KETONES

The stereo- and regiochemistry of addition of the enolates of ketones and esters to α,β-unsaturated ketones has been studied. There is a strong correlation between the enolate geometry and adduct stereostructure, with E enolates forming syn products and Z enolates yielding anti products. With few exceptions, both the syn and anti adducts can be obtained in good to excellent diastereomeric excess. The results are consistent with a chelated, eight-membered transition state. © 1990, American Chemical Society. All rights reserved.