Confirmation by trapping, synthesis, and reactivity of 2,3-dehydro-N-methylmorpholine (DNMM)

DNMM (5) was synthesized from formmorpholide (16) in 3 steps in 38% overall yield. The compound was shown to occur as degradation product in thermal reactions of NMMO (1) by trapping with the α-tocopherol-derived ortho-quinone methide (oQM, 8) in an inverse hetero-Diels-Alder reaction.