Remarkable Lewis acid mediated enhancement of enantioselectivity during free-radical reductions by simple chiral non-racemic stannanes
作者:Dainis Dakternieks、Kerri Dunn、V. Tamara Perchyonok、Carl H. Schiesser
DOI:10.1039/a904700j
日期:——
Additions of 1 equiv. of achiral and chiral Lewis acidsto free-radical reduction reactions involving (1S,2S,5R)-menthyldiphenyltin hydride 1, bis[(1S,2S,5R)-menthyl]-phenyltin hydride 2, bis[1S,2S,5R)-menthyl][8-(N,N-dimethylamino)naphthyl]tin hydride 3, bis[(1R,2S,5R-menthyl]1-(S)-N,N-dimethylaminoethyl]phenyl}tin hydride 4 or 3α-dimethylstannyl-5α-cholestane 5 result in remarkable increases in enantioselectivity.
添加1当量的非手性和手性路易斯酸到涉及(1S,2S,5R)-薄荷基二苯基锡氢化物1、双[(1S,2S,5R)-薄荷基]苯基锡氢化物2、双[(1S,2S,5R)-薄荷基][8-(N,N-二甲氨基)萘基]锡氢化物3、双[(1R,2S,5R-薄荷基]1-(S)-N,N-二甲氨基乙基}苯基}锡氢化物4或3α-二甲基锡基-5α-胆固醇5的自由基还原反应中,能够显著提高对映选择性。