Formation and reaction of 2-metalated N-Boc-4,4-dimethyl-1,3-oxazolidines in the presence of (−)-sparteine: new chiral formyl anion equivalents
作者:Naoki Kise、Tadashi Urai、Jun-ichi Yoshida
DOI:10.1016/s0957-4166(98)00319-x
日期:1998.9
Lithiation of N-Boc-4,4-dimethyl-1,3-oxazolidine with s-BuLi and the following reaction with benzaldehyde was carried out in the presence of (-)-sparteine. The reaction was not diastereoselective (syn:anti=46:54), but each isomer of the adducts was obtained enantioselectively (syn: 90% ee, anti: 88% eel. Addition of MgBr2 to the reaction mixture increased the diastereoselectivity to syn:anti=90:10. (C) 1998 Elsevier Science Ltd. All rights reserved.