Is an iodine atom almighty as a leaving group for Bu3SnH-mediated radical cyclization?: The effect of a halogen atom on the 5-endo-trig radical cyclization of N-vinyl-α-halo amides

被引：47

作者：

Tamura, O ^{[1
]}

Matsukida, H ^{[1
]}

Toyao, A ^{[1
]}

Takeda, Y ^{[1
]}

Ishibashi, H ^{[1
]}

机构：

[1] Kanazawa Univ, Fac Pharmaceut Sci, Kanazawa, Ishikawa 9200934, Japan

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2002年 / 67卷 / 16期

关键词：

D O I：

10.1021/jo020007u

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The effect of a halogen atom as a leaving group on Bu3SnH-mediated 5-endo-trig radical cyclization of N-(cyclohex-l-enyl) alpha-halo amides was examined. The cyclization of alpha-chloro amides occurred with a high degree of efficiency, whereas the corresponding alpha-iodo congeners gave only limited quantities of cyclization products. A detailed study revealed that these phenomena could be attributed to the initial conformations of alpha-halo amides. The cyclizing ability of alpha-iodo amides can be restored with Bu3SnCl or Bu3SnF as an additive. The cyclization of an alpha-iodo amide in the presence of Bu3SnF could be applied to a short-step synthesis of lycoranes featuring sequential 5-endo-trig and 6-endo-trig radical cyclizations.

引用

页码：5537 / 5545

页数：9

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