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

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journal contribution
posted on 09.11.2007, 00:00 authored by Jamie L. Zigterman, Jacqueline C. S. Woo, Shawn D. Walker, Jason S. Tedrow, Christopher J. Borths, Emilio E. Bunel, Margaret M. Faul
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.