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.