Reactions of unactivated olefins with Vilsmeier reagents

Abstract

Reactions of N-formylmorpholine/POCl 3 with several unactivated olefins yield the corresponding α,β-unsaturated aldehydes. Norbornene affords with dimethylformamide/POCl 3 a product formed by a novel inverse-electron demand Diels–Alder reaction of an acyclic 2-azoniodiene. The structure of this product was confirmed by X-ray analysis. Crystals are monoclinic: a = 8.025(3), b = 11.670(3), c = 9.309(4) Å, β = 108.03(3)°, P2 1 , Z = 2; the structure was refined to R = 0.044 for 1379 independent observed reflections.