Efficient Synthesis of <i>Ephedra</i> Alkaloid Analogues Using an Enantiomerically Pure <i>N</i>-[(<i>R</i>)-(+)-α-Methylbenzyl]aziridine-2-carboxaldehyde
作者:Gwon-Il Hwang、Jae-Ho Chung、Won Koo Lee
DOI:10.1021/jo9603183
日期:1996.1.1
Efficient preparation of enantiomerically pure (2S)-aziridine-2-carboxaldehyde 9 and its 2(R) isomer and highly diastereoselective addition of organolithium reagents to the aldehyde 9 are described. The diastereoselectivity in additions of the lithium reagents seems to come from "chelation-controlled" carbon-carbon bond formation and is influenced by the source of the organometallic compound, solvent
描述了对映体纯的(2S)-氮丙啶-2-甲醛9及其2(R)异构体的高效制备以及向醛9中高度非对映选择性地添加有机锂试剂。锂试剂中的非对映选择性似乎来自“螯合控制的”碳-碳键的形成,并受有机金属化合物的来源,溶剂和锂盐的存在的影响。加成产物的氮丙啶环的C(3)-N键在Pearlman催化剂的存在下通过催化氢化而区域选择性地还原,从而提供对映体纯的1,2-氨基醇。与市售的正伪麻黄碱相比,当C-1取代基为苯基时,将氨基醇13a的绝对立体化学指定为(1S,2S)。