Practical, efficient, and broadly applicable synthesis of readily differentiable vicinal diboronate compounds by catalytic three-component reactions.

A practical, efficient and broadly applicable catalytic method for synthesis of easily differentiable vicinal diboronate compounds is presented. Reactions are promoted by a combination of PCy3 or PPh3, CuCl and LiOt-Bu and may be performed with readily accessible alkenyl boronate substrates. Through the use of an alkenyl-B(pin) (pin = pinacolato) or alkenyl- B(dan) (dan = naphthalene-1,8-diaminato) starting material and commercially available (pin)B- B(dan) or B2(pin)2 as the reagent, a range of vicinal diboronates, including those that contain a B-substituted quaternary carbon center, may be prepared in up to 91% yield and with >98% site selectivity. High enantioselectivities can be obtained (up to 96:4 er) through the use of commercially available chiral bis-phosphine ligands for reactions that afford mixed diboronate products.