Efficient total syntheses of pumiliotoxins A and B. Applications of iodide-promoted iminium ion - Alkyne cyclizations in alkaloid construction

被引：65

作者：

Lin, NH ^{[1
]}

Overman, LE ^{[1
]}

Rabinovitz, MH ^{[1
]}

Robinson, LA ^{[1
]}

Sharp, MJ ^{[1
]}

Zablocki, J ^{[1
]}

机构：

[1] UNIV CALIF IRVINE,DEPT CHEM,IRVINE,CA 92717

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 1996年 / 118卷 / 38期

关键词：

D O I：

10.1021/ja961641q

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

A practical route for the total synthesis of pumiliotoxin A alkaloids is described. The central step is formation of the piperidine ring and establishment of the (Z)-alkylidene side chain by an iodide-promoted iminium ion-alkyne cyclization. The total synthesis of (+)-15(S)-pumiliotoxin A (2) was realized in 5 steps and 32% overall yield from alkyne 36 and epoxide 7, This synthesis of 2 proceeded in 13 steps and 12% overall yield from (S)-2-methyl-1-penten-3-ol (25) and 8 steps and 9% overall yield from N-[(benzyloxy)carbonyl]-L-proline. The synthesis of (+)-pumilioloxin B (3) was similarly achieved in four steps and 44% overall yield from alkyne 54 and epoxide 7. The overall yield of enantiopure 3 was 8% from N-[(benzyloxy)carbonyl]-L-proline and 10% from (4S,5R)-4-methyl-5-phenyl-2-oxazolidinone. These syntheses represent substantial improvement over previous routes to these important alkaloids.

引用

页码：9062 / 9072

页数：11

共 41 条

[1]

[Anonymous], 1993, ALKALOIDS CHEM PHARM

[2]

ARNOLD H, 1991, ORG SYNTH, V70, P111

[3] TOXICITY OF PUMILIOTOXIN 251D AND SYNTHETIC ANALOGS TO THE COTTON PEST HELIOTHIS-VIRESCENS [J].