Highly Selective Rhodium-Catalyzed Conjugate Addition Reactions of 4-Oxobutenamides

A variety of 4-oxobutenamides 1 were subjected to rhodium-catalyzed conjugate addition with arylboronic
acids providing high regio- and enantioselectivity (97:3 to >99:1, >96% ee) and moderate to excellent
yields (54−99%). The key to high selectivity is the use of sterically demanding P-chiral diphosphines,
such as Tangphos or Duanphos. The product oxobutanamides 2 may be converted to alternate targets by
selective derivatization of either the amide or ketone functional group. A stereochemical model predicting
the absolute sense of induction was developed based on single-crystal X-ray structures of product and
precatalyst.