Single enantiomer free-radical chemistry—Lewis acid-mediated reductions of racemic halides using chiral non-racemic stannanes
作者:Dainis Dakternieks、V.Tamara Perchyonok、Carl H. Schiesser
DOI:10.1016/j.tetasy.2003.07.012
日期:2003.10
Additions of one to two equivalents of Lewis acids that include magnesium salts to free-radical reduction reactions involving ester functionalized radicals and (1R,2S,5R)-menthyldiphenyltin hydride 4, bis((1R,2S,5R)-menthyl)phenyltin hydride 5, tris((1R,2S,5R)-menthyl)tin hydride 6, bis((1R,2S,5R)-menthyl)-[8-(N,N-dimethylamino)naphthyl]tin hydride 12, bis((1R,2S,5R)-menthyl)-[1-((S)-N,N-dimethyla
在涉及酯官能化自由基和(1 R,2 S,5 R)-薄荷基二苯基锡氢化物4,bis(((1 R,2 S,5 R)-薄荷基)苯基氢化锡5,三((1 R,2 S,5 R)-薄荷基)氢化锡6,双((1 R,2 S,5 R)-薄荷基)-[8-(N,N -二甲基氨基)萘]锡氢化物12,bis((1 R,2 S,5 R)-薄荷基)-[1-((S)-N,N-二甲基氨基乙基)苯基]氢化锡13或3α-二甲基锡烷基-5α-胆甾烷14产生显着的对映选择性。实例包括(S)-萘普生乙酯16(在MgBr 2的存在下在-78°C下由溴化物和5以74%的收率和大于99%ee的产率生产)和乙基(R)-N-三氟乙酰基-d -甘氨酸苯基酯18在相同条件下,收率分别为78%和99%ee。动力学和计算研究为这些观察的起源提供了见识。