Enantioselective Titanium-Mediated Vinylaluminum Addition to Ketones

Significance

While allyltin, -silicon, and -boron ­reagents are common for vinyl addition reactions to aldehydes, vinyl additions to less reactive ­ketones remain relatively undeveloped. Recently, the authors have shown that [AlAr₃(THF)] reagents are reactive nucleophiles for the titanium-catalyzed ­addition to aldehydes and ketones. Based on Hoveyda’s work (J. Am. Chem. Soc. 2008, 130, 446), the authors report the asymmetric addition of vinylaluminum reagents to aryl methyl ketones mediated by titanium. Substrate scope is quite general, affording chiral tertiary alcohols in high yields and ee values.