Synthesis of chiral alcohols by asymmetric reductions of various ketones including α-aminophenones
摘要:
LiAlH4 previously treated with 2.5 equiv. of (S)-(+) or (R)-(-)-2-(2-isoindolinyl)butan-1-ol 1 reduced the six alpha-aminophenones 4-9 into the corresponding optically active beta-aminoalcohols 10-15 whose ee's were in the range 40-97% after chromatography and recrystallization. The asymmetric reduction of the ortho-dimethylaminobenzophenone 18, using the same reducing agents afforded the enantiomerically pure benzhydrols (R)-(-)-19 and (S)-(+)-19, respectively, and in 86-100% yields. The ortho-aminobenzhydrol (S)-(+)-20 and a-fluorenyl ethanol (R)-(+)-23 and (S)-(-)-23 were similarly obtained from the corresponding ketones 17 and 25, respectively. The latter carbinols were obtained in an enantiomerically pure state after recrystallization. Copyright (C) 1996 Elsevier Science Ltd
Synthesis of chiral alcohols by asymmetric reductions of various ketones including α-aminophenones
摘要:
LiAlH4 previously treated with 2.5 equiv. of (S)-(+) or (R)-(-)-2-(2-isoindolinyl)butan-1-ol 1 reduced the six alpha-aminophenones 4-9 into the corresponding optically active beta-aminoalcohols 10-15 whose ee's were in the range 40-97% after chromatography and recrystallization. The asymmetric reduction of the ortho-dimethylaminobenzophenone 18, using the same reducing agents afforded the enantiomerically pure benzhydrols (R)-(-)-19 and (S)-(+)-19, respectively, and in 86-100% yields. The ortho-aminobenzhydrol (S)-(+)-20 and a-fluorenyl ethanol (R)-(+)-23 and (S)-(-)-23 were similarly obtained from the corresponding ketones 17 and 25, respectively. The latter carbinols were obtained in an enantiomerically pure state after recrystallization. Copyright (C) 1996 Elsevier Science Ltd
Preparative synthesis of optically pure ortho-substituted benzhydrols by asymmetric reductions of the corresponding benzophenones
作者:Eric Brown、Antoine Lézé、Joël Touet
DOI:10.1016/s0957-4166(00)82179-5
日期:1992.7
Lithium aluminium hydride previously treated with 2.5 equivalents of (S)-(+) or (R)-(-)-2 -(2-iso-indolinyl)butan-1-ol 3 (readily available reagents) reduced the five ortho-substituted benzophenones 4-6, 8 and 10 into the corresponding optically active benzhydrols with nearly 100% enantiomeric excesses. Other examples of asymmetric reductions of prochiral benzophenones are given.
Synthesis of chiral alcohols by asymmetric reductions of various ketones including α-aminophenones
作者:Eric Brown、Antoine Lézé、Joël Touet
DOI:10.1016/0957-4166(96)00245-5
日期:1996.7
LiAlH4 previously treated with 2.5 equiv. of (S)-(+) or (R)-(-)-2-(2-isoindolinyl)butan-1-ol 1 reduced the six alpha-aminophenones 4-9 into the corresponding optically active beta-aminoalcohols 10-15 whose ee's were in the range 40-97% after chromatography and recrystallization. The asymmetric reduction of the ortho-dimethylaminobenzophenone 18, using the same reducing agents afforded the enantiomerically pure benzhydrols (R)-(-)-19 and (S)-(+)-19, respectively, and in 86-100% yields. The ortho-aminobenzhydrol (S)-(+)-20 and a-fluorenyl ethanol (R)-(+)-23 and (S)-(-)-23 were similarly obtained from the corresponding ketones 17 and 25, respectively. The latter carbinols were obtained in an enantiomerically pure state after recrystallization. Copyright (C) 1996 Elsevier Science Ltd