Ester-stabilised alpha,beta:gamma,delta-unsaturated azomethine ylides 9 were generated by the deprotonation method from isoquinolinium salts 8. 1,7-Electrocyclisation of these dipoles followed by a 1,5-hydrogen shift, gives tetrahydro[5,6]azepino[2,1-a]isoquinolines 10. (C) 2003 Elsevier Science Ltd. All rights reserved.