An expeditious synthesis of 3-(difluoromethoxy)- and 3-(trifluoromethoxy)-5,6,7,8-tetrahydro-1,6-naphthyridines

An expeditious and concise synthesis of 3-(difluoromethoxy)-5,6,7,8-tetrahydro-1,6-naphthyridine and 3-(trifluoromethoxy)-5,6,7,8-tetrahydro-1,6-naphthyridines is described. Starting from N-benzyl piperidone, the key intermediates leading to these two biologically desirable synthones were rapidly assembled by inverse electron demand Diels–Alder (IEDA) reaction utilizing microwave irradiation. The scope of the microwave methodology developed herein was extended to other ketones.