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 α,β‐diketoamides resulted in high yields (91–99 %) of β‐crotylated products obtained as a single diastereomer (anti), Lewis acid promoted crotylboration of α,β‐diketo esters yielded the α‐crotylated species with the anti product as main diastereomer. (E)‐Crotylboration of α,β‐diketoamides resulted in high yields (91–99 %) of β‐crotylated products obtained as a single diastereomer (anti). Lewis acid promoted crotylboration of α,β‐diketo esters yielded the α‐crotylated species with the anti product as main diastereomer.