Ligand-catalyzed asymmetric alkynylboration of enones: a new paradigm for asymmetric synthesis using organoboranes.
Asymmetric conjugate alkynylation of enones may be effected using a B-1-alkynyldiisopropylboronate and catalytic amounts of binaphthol ligands. The high enantioselectivities observed are comparable to those obtained using stoichiometric amounts of binaphthol-modified boronate reagents, suggesting that this is a ligand-accelerated process. This is the first demonstration that catalytic amounts of chiral diols can be used with boronates to effect high levels of stereochemical control.
Wu
T Robert
TR
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Chong
J Michael
JM