Sc(III)-Catalyzed Syn-Selective Enantioselective Carbonyl Ene Reactions
D. A. Evans*, J. Wu
Harvard University, Cambridge, USA
21 September 2005 (online)
Numerous metals such as Co, Pd, Pt, Cr, and Cu have been found to catalyze the carbonyl ene reaction of unactivated alkenes. Unfortunately, these reactions generally suffer from moderate yields and ee’s. A variety of disubstituted terminal olefins were reacted with N-phenylglyoxamide to give carbonyl ene products in good yield and with excellent ee. When trisubstituted olefins were used, a second stereogenic center was created with syn stereoselectivity and high ee. Finally, the use of a Z-substituted allylsilane as enophile was shown to give complementary anti products with good yields, enantio- and diastereoselectivities.