Synthesis of protoberberines using a silyl-directed Pictet-Spengler cyclization

被引：39

作者：

Cutter, PS ^{[1
]}

Miller, RB ^{[1
]}

Schore, NE ^{[1
]}

机构：

[1] Univ Calif Davis, Dept Chem, Davis, CA 95616 USA

来源：

TETRAHEDRON | 2002年 / 58卷 / 08期

基金：

美国国家科学基金会;

关键词：

enantioselective; ipso-substitution; Pictet-Spengler reaction; protoberberine; regioselectivity; silyl-direction;

D O I：

10.1016/S0040-4020(02)00010-8

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Five naturally-occurring protoberberines have been synthesized in enantioenriched form by alkylation by two different 2-trimethylsilylbenzyl chlorides of four tetrahydroisoquinolines, derivatized with Meyers' formamidine valinol methyl ether chiral auxiliary. Silyl-directed Pictet-Spengler cyclization of the ensuing 3,4-dimethoxy-2-trimethylsilylbenzyl tetrahydroisoquinolines leads to four of the target protoberberines in excellent yield and complete regioselectivity. In the fifth case, the 3,4-methylenedioxy analog gives a mixture of protoberberine and a product of ring closure at C6 of the benzyl moiety in a 3:4 ratio. (C) 2002 Published by Elsevier Science Ltd.

引用

页码：1471 / 1478

页数：8

共 39 条

[1]

BAFFELEY G, 1956, J CHEM SOC, P2455

[2]

BHAKUNI DS, 1986, ALKALOIDS, V28, P95

[3]

Bischler A., 1893, CHEM BER-RECL, V26, P1903, DOI DOI 10.1002/CBER.189302602143

[4]

BROADBENT TA, 1983, HETEROCYCLES, V20, P863