Free radical cyclizations in alkaloid total synthesis: (+/-)-21-oxogelsemine and (+/-)-gelsemine

被引：82

作者：

Atarashi, S ^{[1
]}

Choi, JK ^{[1
]}

Ha, DC ^{[1
]}

Hart, DJ ^{[1
]}

Kuzmich, D ^{[1
]}

Lee, CS ^{[1
]}

Ramesh, S ^{[1
]}

Wu, SC ^{[1
]}

机构：

[1] OHIO STATE UNIV, DEPT CHEM, COLUMBUS, OH 43210 USA

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 1997年 / 119卷 / 27期

关键词：

D O I：

10.1021/ja970089h

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Total syntheses of (+/-)-21-oxogelsemine (3) and (+/-)-gelsemine (1) are described. Free radical cyclizations play important roles in constructing the tricyclic core (40 --> 41) and oxindole (93 --> 96) substructures of the target alkaloids, and an isomerization-cyclization strategy (101 --> 102) was used to complete construction of the gelsemine cage. Observations made along the way include intramolecular 1,4- and 1,6-hydrogen atom transfers (64 --> 65 and 40 --> 47) and a free radical cyclization-fragmentation sequence (85 --> 86 + 87). A retroaldol-aldol strategy for adjusting oxindole stereochemistry in gelsemine-like structures is also described (72 --> 74 and 86 --> 87).

引用

页码：6226 / 6241

页数：16

共 76 条

[1] INTRAMOLECULAR ALKENE ARYLATIONS FOR RAPID ASSEMBLY OF POLYCYCLIC SYSTEMS CONTAINING QUATERNARY CENTERS - A NEW SYNTHESIS OF SPIROOXINDOLES AND OTHER FUSED AND BRIDGED RING-SYSTEMS [J].