Polyhydroxylated pyrrolizidines. Part 4: Total asymmetric synthesis of unnatural hyacinthacines from a protected derivative of DGDP
作者:Isidoro Izquierdo、Marı́a T Plaza、Francisco Franco
DOI:10.1016/j.tetasy.2004.03.013
日期:2004.5
(1R,2R,3S,5R,7aR)-1,2-Dihydroxy-3-hydroxymethyl-5-methylpyrrolizidine [(+)-3-epi-hyacinthacine A(3)] 1 and (1R,2R,3S,7aR)-1,2-dihydroxy-3-hydroxymethylpyrrolizidine [(+)-3-epi-hyacinthacine A(2)] 2 have been synthesized by Wittig's methodology using aldehyde 6, prepared from (2R,3R,4R,5S)-3,4-dibenzyloxy-N-benzyloxycarbonyl-2'-O-tent-butyldiphenylsilyl-2,5-bis(hydroxymethyl) pyrrolidine 3 (a partially protected DGDP), and the appropriated ylides, followed by cyclization through an internal reductive amination process of the resulting alpha,beta-unsaturated ketone 7 and aldehyde 8, respectively, and total deprotection. (C) 2004 Elsevier Ltd. All rights reserved.
(1R,2R,3S,5R,7aR)-1,2-二羟基-3-(羟甲基)-5-甲基吡咯烷二酮 [(+)-3-表海葱素 A(3)] 1 和 (1R,2R,3S,7aR)-1,2-二羟基-3-(羟甲基)吡咯烷二酮 [(+)-3-表海葱素 A(2)] 2 是通过 Wittig 方法[1](使用由 (2R,3R,4R,5S)-3,4-二苯氧基-N-苯氧羰基-2'-O-(特丁基二苯基)硅基-2,5-双(羟甲基)吡咯烷[2](部分保护的 DGDP)制备的醛 6 以及相应的亚甲基, 然后分别通过 α,β-不饱和酮 7 和醛 8 的内源性还原胺化步骤进行环化, 最后完成完全脱保护而合成的。 (C) 2004 Elsevier Ltd. 保留所有权利。
[1] Wittig 方法:一种用于构建碳-碳双键的化学反应方法,通常涉及将醛或酮与 Wittig 试剂(如亚甲基化合物)反应生成烯烃。
[2] DGDP:二羟基-PDOT(双(羟甲基)吡咯烷)的缩写形式。