Scandium triflate catalyzes the addition of camphor-derived allyl-, methallyl-, and
crotylboronates to aldehydes to provide homoallylic alcohols with excellent diastereo-
and enantioselectivity. Aromatic, aliphatic, and propargylic aldehydes can be used
successfully in this system. Additional advantages of the camphor-diol allylboronates
are their ease of synthesis, their availability in both enantiomeric forms, and their
stability towards silica gel chromatography. The usefulness of this methodology is
further demonstrated by the gram-scale synthesis of various homoallylic alcohols of
high enantiomeric excess and by the concise synthesis of the pheromone (4S)-2-methyloctan-4-ol.
allylations - chiral auxiliaries - crotylations - Lewis acids - scandium