Lithium Binaphtholate-Catalyzed Enantioselective Enyne Addition to Ketones: Access to Enynylated Tertiary Alcohols

A new catalytic enantioselective enyne addition to ketones has been developed. In the presence of chiral lithium binaphtholate, the addition reaction proceeded smoothly to produce a series of enynylated tertiary alcohols in up to 96% yield and 94% enantiomeric excess. Convenient transformation of the adduct via Pauson-Khand cycloaddition reaction afforded the bicyclic product without detectable loss of enantioselectivity. Furthermore, catalytic asymmetric enyne addition to trifluoromethylketone was applied in the synthesis of the Efavirenz analogue.