Photoaddition of alkenes to conjugated alpha-diketones: Tandem cyclizations leading to tetrasubstituted furans

被引：16

作者：

Mukherjee, AK ^{[1
]}

Margaretha, P ^{[1
]}

Agosta, WC ^{[1
]}

机构：

[1] LABS ROCKEFELLER UNIV, NEW YORK, NY 10021 USA

来源：

JOURNAL OF ORGANIC CHEMISTRY | 1996年 / 61卷 / 10期

关键词：

D O I：

10.1021/jo952079+

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Photocycloaddition of 9a-c with 2 leads cleanly to tetrasubstituted furans 12a-c, respectively, in yields of similar to 85%. The reactive triplet is efficiently sensitized by 2-benzoylnaphthalene and quenched by anthracene, indicating that E(T) is in the range 43-58 kcal/mol. A mechanism is proposed involving an alkyl propargyl biradical (as 10) that closes first to a vinyl carbene (as 11) and then to product. Reaction of 9c with 20 furnishes only 22, and this result rules out an alternative mechanism in which the order of steps leading to the carbene is reversed.

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页码：3388 / 3391

页数：4

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