Synthesis of substituted pyrano[3,2-c]pyridines via Diels-Alder reaction of 3-methylenepyridin-4-one
On heating, the di-Boc-pyridin-4-one derivative 7 gave an unstable 3-methylenepyridin-4-one intermediate 3, which underwent a rearomatising Diels-Alder cycloaddition with activated alkenes to give substituted pyrano[3,2-c]pyridines in moderate yields.
Tchabanenko, Kirill,Taylor, Marcus G. O.,Adlington, Robert M.,Baldwin, Jack E.