DIMERIZATION OF INDOLIZINES BY PALLADIUM COAL

Oxidative dimerisation of some indolizines by Pd/C in p-xylene was und ertaken in order to evaluate reaction conditions for cyclophane synthe ses. Surprisingly, alkylation by the solvent occurred at the 3-positio n of the indolizines 2 and 5 as a side reaction. In toluene, yields of alkylation products 4b and 8 exceeded those of dimerisation products 3 and 6. The alkylation by the solvent was fully suppressed by using c hlorobenzene or chlorotoluene. Alkylation products of indolizines with p-xylene or toluene and previously unknown dimeric indolizines are de scribed.