The asymmetric synthesis of (-)-codonopsinine was achieved in 7 steps (from commercially available tert-butyl crotonate) in 5% overall yield and >99:1 dr. The key step in this synthesis involved ring-closing iodoamination of a functionalised homoallylic amine, which occurred with concomitant N-debenzylation, to give a 3-iodopyrrolidine that was elaborated to (-)-codonopsinine. (C) 2011 Elsevier Ltd. All rights reserved.
Ring-closing iodoamination of homoallylic amines for the synthesis of polysubstituted pyrrolidines: application to the asymmetric synthesis of (−)-codonopsinine
摘要:
Ring-closing iodoamination of (E)-configured, N-alpha-methyl-p-methoxybenzyl protected homoallylic amines upon treatment with 12 and NaHCO3 in MeCN occurs with concomitant loss of the N-alpha-methyl-p-methoxybenzyl group to give 3-iodopyrrolidines in >99:1 dr. This transformation was used as one of the key steps in the total asymmetric synthesis of (-)-codonopsinine, which was achieved in seven steps (from commercially available tert-butyl crotonate) in 5% overall yield and >99:1 dr. (c) 2012 Elsevier Ltd. All rights reserved.
Ring-closing iodoamination of homoallylic amines for the synthesis of polysubstituted pyrrolidines: application to the asymmetric synthesis of (−)-codonopsinine
作者:Stephen G. Davies、James A. Lee、Paul M. Roberts、James E. Thomson、Callum J. West
DOI:10.1016/j.tet.2012.03.045
日期:2012.6
Ring-closing iodoamination of (E)-configured, N-alpha-methyl-p-methoxybenzyl protected homoallylic amines upon treatment with 12 and NaHCO3 in MeCN occurs with concomitant loss of the N-alpha-methyl-p-methoxybenzyl group to give 3-iodopyrrolidines in >99:1 dr. This transformation was used as one of the key steps in the total asymmetric synthesis of (-)-codonopsinine, which was achieved in seven steps (from commercially available tert-butyl crotonate) in 5% overall yield and >99:1 dr. (c) 2012 Elsevier Ltd. All rights reserved.
Asymmetric synthesis of (−)-codonopsinine
作者:Stephen G. Davies、James A. Lee、Paul M. Roberts、James E. Thomson、Callum J. West
DOI:10.1016/j.tetlet.2011.09.114
日期:2011.11
The asymmetric synthesis of (-)-codonopsinine was achieved in 7 steps (from commercially available tert-butyl crotonate) in 5% overall yield and >99:1 dr. The key step in this synthesis involved ring-closing iodoamination of a functionalised homoallylic amine, which occurred with concomitant N-debenzylation, to give a 3-iodopyrrolidine that was elaborated to (-)-codonopsinine. (C) 2011 Elsevier Ltd. All rights reserved.