Enantioselective Cyclization/Hydrosilylation of 1,6-Enynes Catalyzed by a Cationic Rhodium Bis(phosphine) Complex

Abstract

[reaction: see text] Reaction of 4,4-dicarbomethoxy-1-octene-6-yne (1) with triethylsilane and a catalytic 1:1 mixture of [Rh(COD)(2)](+) SbF(6)(-) and (R)-BIPHEMP (5 mol %) at 70 degrees C for 90 min gave (Z)-1,1-dicarbomethoxy-3-(1-triethylsilyl)ethylidene-4-methylcyclopentane (2) in 81% isolated yield with 98% de and 92% ee.