Titanium-Catalyzed Reaction of Alkenylboron Reagents with Aldehydes

Significance

Allylic alcohols are important building blocks in organic synthesis and much attention has been focused on their synthesis. The ­reaction of alkenylboron reagents with aldehydes represents a straightforward and modular approach to allylic alcohols. Previously, the authors reported the titanium-catalyzed asymmetric ­addition of alkylboranes to aldehydes (T. Ukon, T. Harada, Eur. J. Org. Chem. 2008, 4405), and they now present the titanium-catalyzed asymmetric addition of alkenylboranes to aldehydes. Oppolzer had reported the amino alcohol catalyzed addition of organozincs to aldehydes, where the organozincs were generated in situ via transmetalation from the organoboranes (W. Oppolzer, R. N. Radinov Helv. Chim. Acta 1992, 75, 170).