Polyhydroxylated pyrrolizidines. Part 8. Enantiospecific synthesis of looking-glass analogues of hyacinthacine A5 from DADP
作者:Isidoro Izquierdo、María T. Plaza、Juan A. Tamayo、Miguel Rodríguez、Alicia Martos
DOI:10.1016/j.tet.2006.04.003
日期:2006.6
(1R,2S,3S,5R,7aR)-1,2-Dihydroxy-3-hydroxymethyl-5-methylpyrrolizidine[(-)-3-epihyacinthacine A(5), 1a] and (1S,2R,3R,5S 7aS)-1,2-dihydroxy-3-hydroxymethylpyrrolizidine[(+)-3-epihyacinthacine A5, 1b] have been synthesized either by Wittig's or Horner-Wadsworth-Emmond's (HWE's) methodology using aldehydes 4 and 9, both prepared from (2S,3S,4R,5R)-3,4-dibenzyloxy-2'-O-tert-butyldiphenylsilyl-2,5-bis(hydroxymethyl)pyrrolidine (2, partially protected DADP), and the appropriate ylides, followed by cyclization through an internal reductive amination process of the resulting alpha,beta-unsaturated ketones 5 and 10, respectively, and total deprotection. (c) 2006 Elsevier Ltd. All rights reserved.
(1R,2S,3S,5R,7aR)-1,2-二羟基-3-羟甲基-5-甲基吡咯烷[(-)-3-表洋蓟碱A(5), 1a]和(1S,2R,3R,5S,7aS)-1,2-二羟基-3-羟甲基吡咯烷[(+)-3-表洋蓟碱A5, 1b]已通过Wittig法或霍纳-伍德沃德-埃蒙德法(HWE法)合成,分别使用醛4和醛9作为起始材料,这些醛均由(2S,3S,4R,5R)-3,4-二苄氧基-2'-O-叔丁基二苯基硅基-2,5-双(羟甲基)吡咯啶(2,部分保护的DADP)制得,以及适当的叶立德(ylides),随后通过α,β-不饱和酮5和10的还原胺化过程分别进行环化,最后进行完全去保护。© 2006 爱思唯尔有限公司。保留所有权利。