Synthesis of Multisubstituted Pyridines from α-Diazocarbonyl Derivatives

Significance

A one-pot synthesis of substituted pyridines via a reaction of 2-azido-2,4-dienoates with α-diazocarbonyl compounds, both prepared via known procedures, in the presence of triphenylphosphine is reported. A plausible mechanistic scheme involves a Staudinger-Meyer reaction and a Wolff rearrangement of starting materials, combined together via an aza-Wittig reaction, the product of which undergoes an electrocyclic ring closure to afford the pyridines. A mechanism is proposed without evidence. The method seems to be efficient and general, as evidenced by the substrate scope and the high yields.