3, 4-Didehydropyridine plus cyclopentadiene:[2+ 2] or [4+ 2]-cycloaddition?

MG Reinecke, ES Brown, BP Capehart, DE Minter…

Index: Reinecke, Manfred G.; Brown, E. Sherwood; Capehart, Bruce P. Tetrahedron, 1988 , vol. 44, # 18 p. 5675 - 5680

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Citation Number: 9

Abstract

3, 4-Didehydropyridine (2) generated from two precursors (6 and 7) of the diazonium carboxylate 5 reacts with cyclopentadiene to give the [4+ 2]-cyclo-addition product 3 rather than the [2+ 2]-adduct 4 proposed in the literature. The structure of 3 was supported by complete proton and carbon NMR assignments made with the aid of decoupling and 2D experiments.