Asymmetric addition of alkynes to imines in water catalyzed with a recyclable Cu(I)-bis(oxazoline) and stearic acid system

Stearic acid and its zinc salt were used as additives in the enantioselective alkyne addition to imines catalyzed by copper(I)-bis(oxazoline) (box) in water. The reactions took place smoothly with good yields and high enantioselectivities (up to 97% ee). Good enantioselectivities were maintained in a catalyst recycle study. (c) 2007 Elsevier Ltd. All rights reserved.