Lithium TADDOLate-triethylboron system as a promoter for the catalytic enantioselective Michael addition of malonates to chalcone.

The reaction mixture obtained by treating equimolar amounts of a TADDOL with lithium triethylborohydride promotes the catalytic enantioselective Michael addition of malonates to chalcone with good yields and moderate enantioselectivities. The catalyst is alternatively generated reacting the 1,4-diol with butyllithium and triethylborane. The adduct of dibenzyl malonate to chalcone is attained with 99% ee, after one recrystallization. The reaction scale-up was achieved successfully.