Abstract
Robinson-Schöpf cyclisation was used to prepare several 1, 2, 6-trisubstituted-4-piperidones: 1, 2, 6-trimethyl-4-piperidone, tricyclic ketones 2 and 3 derivatives of coccinelline. In the case of 1, 2, 6-trimethyl-4-piperidone, a mixture of the trans and cis compounds 4 and 1 was obtained. The pure cis compound was prepared by another route.