A GENERAL, HIGHLY ANTI-STEREOSELECTIVE ALDOLIZATION METHOD VIA CAMPHOR-DERIVED BORYL ENOLATES

Camphor-derived chiral boryl enolates are highly reactive and highly a nti-stereoselective enolate synthon systems in aldol addition reaction s promoted by a TiCl4 or SnCl4 cocatalyst. More significantly, this hi gh-yield reaction exhibits remarkable generality with respect to the a ldehyde nature, as illustrated by the rapid and anti-stereoselective a ldolizations with the simple saturated and unsaturated aliphatic aldeh ydes, and aromatic aldehydes at temperatures as low as -90 degrees C. The enhanced reaction generality and anti stereoselectivity of camphor -derived boryl enolates suggests the importance of the nature of chira l auxiliary architecture in determining the aldol bond construction pr ocess. Final nondestructive camphor-based auxiliary removal via hydrop eroxide-mediated hydrolysis affords enantiomerically pure anti-beta-hy droxy-alpha-methyl aldol products.