Regio- and Diastereoselective Crotylboration of vic-Tricarbonyl Compounds

Crotylboration of vic-diketoamides and vic-diketo esters was achieved with high diastereoselectivity and complementary regioselectivity. Whereas (E)-crotylboration of alpha,beta-diketoamides resulted in high yields (91-99%) of beta-crotylated products obtained as a single diastereomer (anti), Lewis acid promoted kcrotylboration of alpha,beta-diketo esters yielded the alpha-crotylated species with the anti product as main diastereomer.