Photochemical C2− C6 Cyclization of Enyne− Allenes: Detection of a Fulvene Triplet Diradical in the Laser Flash Photolysis

G Bucher, AA Mahajan, M Schmittel

Index: Bucher, Goetz; Mahajan, Atul A.; Schmittel, Michael Journal of Organic Chemistry, 2008 , vol. 73, # 22 p. 8815 - 8828

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Citation Number: 22

Abstract

A series of enyne− allenes, with and without benzannulation at the ene moiety and equipped with aromatic and carbonyl groups as internal triplet sensitizer units at the allene terminus, was synthesized. Both sets, the cyclohexenyne− allenes and benzenyne− allenes, underwent thermal C2− C6 cyclization exclusively to formal ene products. In contrast, the photochemical C2− C6 cyclization of enyne− allenes provided formal Diels− Alder and/or ...