Stereoselective synthesis of spirofused 3-substituted 2,3,4,4a,5,6-hexahydro- 6H-benzo[c]quinolizine using the tert-amino effect

The interaction of 2-(4-R-piperidino)benzaldehyde and cyclic CH-active compounds occurred as a tandem of Knövenagel condensation and cyclization by tert-amino effect and led to spiro-fused 3-substituted 2,3,4,4a,5,6-hexahydro-6H-benzo[c]quinolizine.