Catalytic asymmetric dialkynylation reaction of α-dinitrone by utilizing tartaric acid ester as a chiral auxiliary

金沢大学理工研究域物質化学系The asymmetric addition of alkynylzinc reagents, prepared in situ from dimethylzinc and 1-alkynes, to α-dinitrones derived from glyoxal and N-(4-isopropylbenzyl)hydroxylamine was investigated by utilizing dicyclohexyl (R,R)-tartrate as a chiral auxiliary. The addition reaction of methyl(2-phenylethynyl)zinc afforded the corresponding optically active C2-symmetric (R,R)-bis(hydroxylamine) derivative with enantioselectivities of 90% and 81% ee by utilizing a stoichiometric and catalytic amount of the tartrate, respectively. Furthermore, the catalytic addition reaction of several alkynylzinc reagents also furnished the corresponding bis(hydroxylamine) with moderate to good enantioselectivities. © 2008 Elsevier Ltd. All rights reserved