Efficient stereoselective synthesis of enantiopure cis- and trans-1,2,4-trisubstituted piperidines
作者:Pablo Etayo、Ramón Badorrey、María D. Díaz-de-Villegas、José A. Gálvez
DOI:10.1016/j.tetasy.2007.10.042
日期:2007.11
Enantiomerically pure (2R,4S)- and (2R,4R)-2-[(S)-1,2-dibenzyloxyethyl]-4-[2-(diphenylmethoxy)ethyl]-1-[(S)-1-phenylethyl]piperidines cis-1 and trans-1 have been synthesised from N-[(S)-1-phenylethyl]-(S)-2,3-di-O-benzylglyceraldimine in six steps in 31% and 18% overall yields, respectively. The efficiency of the synthetic strategy developed for the synthesis of these compounds relies on: (a) the totally
对映体纯的(2 R,4 S)-和(2 R,4 R)-2-[(S)-1,2-二苄氧基乙基] -4- [2-(二苯基甲氧基)乙基] -1-[(S) -1-苯乙基]哌啶的顺式- 1和反式- 1已从合成ñ [( -小号)-1-苯基乙基] - (小号)-2,3-二- ö-苄基丙二胺分六步进行,总收率分别为31%和18%。为合成这些化合物而开发的合成策略的效率取决于:(a)Danishefsky的二烯与起始的丙二胺之间的完全非对映选择性的串联曼尼希-迈克尔反应,(b)4-哌啶酮的高产率Wadsworth-Emmons反应(c)哌啶环C 4上的环外C–C双键的非对映异构还原。这些转化导致1,2,4-三取代的哌啶具有两个新的立体异构中心,具有出色的立体选择性。