Synthesis of procyanidins by stepwise- and self-condensation using 3,4-cis-4-acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-benzyl-(+)-catechin and (-)-epicatechin as a key building monomer
Synthesis of procyanidins by stepwise- and self-condensation using 3,4-cis-4-acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-benzyl-(+)-catechin and (-)-epicatechin as a key building monomer
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DOI：
10.1016/j.tetlet.2008.02.173
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发表时间：
2008-05-05
影响因子：
1.8
通讯作者：
Kondo, Tadao
中科院分区：
文献类型：
--
作者：
Oyama, Kin-Ichi;Kuwano, Miyuki;Kondo, Tadao
3，4-cis-4-Acetoxy-3-O-acetyl-4-dehydro-5，7，3‘，4’-tetra-O-benzyl-(+)-catechin(1a)或(-)-表儿茶素(1b)与1.5当量的5，7，3‘，4’-四-O-苯氧基黄烷-3-醇(4a或4b)在1当量的TMSOTf存在下发生区域和立体选择性反应，得到相应的原花青素。另一方面，La在催化量的B(C6F5)(3)存在下的自我缩合提供了从二聚体到15聚体的广泛的原花青素，如生物体。(C)2008爱思唯尔有限公司。保留所有权利。
3,4-cis-4-Acetoxy-3-O-acetyl-4-dehydro-5,7,3',4'-tetra-O-benzyl-(+)-catechin (1a) or (-)-epicatechin (1b) reacted high regio- and stereo-selectively with 1.5 equiv of the 5,7,3',4'-tetra-O-benzyloxyflavan-3-ol (4a or 4b) in the presence of 1 equiv of TMSOTf to give the corresponding procyanidins. On the other hand, the self-condensation of la in the presence of a catalytic amount of B(C6F5)(3) afforded wide-range procyanidins from dimer to 15-mer like a biomass. (C) 2008 Elsevier Ltd. All rights reserved.