192. One-Pot Synthesis of Highly Functionalized Pyridines via a Rhodium Carbenoid Induced Ring Expansion of Isoxazoles

Authors: James R. Manning and Huw M. L. Davies

J. Am. Chem. Soc.,

2008, 130 (27), 8602–8603


A concise one-pot synthesis of highly functionalized pyridines has been developed. The first step in the reaction sequence is the formal insertion of rhodium vinylcarbenoids across the N−O bond of isoxazoles. Upon heating, the insertion products undergo a rearrangement to give 1,4-dihydropyridines. DDQ oxidation then affords the corresponding pyridines in 31−84% yield. The process has proven general with a range of carbenoid and isoxazole components and represents a unique disconnection strategy for the synthesis of functionalized pyridines.

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