Thermal Dearomative Rearrangement of α-(Prop-2-enyl)-α’-(pyridin-2-yl) Malonates Derivatives towards 4H-Dihydroquinolizine.

Reported herein is a thermally induced dearomative rearrangement of α-(aza-heteroaryl)-α’-prop-2-enyl malonate derivatives, af-fording 4H-dihydroquinolizine derivatives (21 examples, 26-94%). The rearrangement assisted by microwave heating afforded diastereoselectively quinolizidine scaffolds, known for their broad biological activities. Experimental results and DFT calculations converge to support a stepwise mechanism initiated by intramolecular [1,4]-addition of the pyridine nitrogen to the activated acry-late moiety, followed by a selective ester transfer.