A conformationally restricted perhydro-1,3-benzoxazine derived from (−)-8-aminomenthol behaves as a
good chiral ligand in the dimethylzinc-mediated enantioselective monoaddition of aromatic and aliphatic
terminal alkynes to 1,2-diketones. The corresponding α-hydroxyketones were obtained in good yields
with high enantioselectivities starting from both aromatic and aliphatic 1,2-diketones. The alkynylation of
unsymmetrical 1,2-diketones with electronically different substituents also proceeds with high regio- and
enantioselectivity. This reaction provides a practical method to synthesize ketones bearing a chiral tertiary
propargylic alcohol.
