HYDROFORMYLATION AND HYDROCARBETHOXYLATION OF 1,2-DICARBETHOXY-1,2,3,6-TETRAHYDROPYRIDAZINE AND 1,2-DICARBETHOXY-1,2,3,4-TETRAHYDROPYRIDAZINE

The unsaturated compounds 1,2-dicarbethoxy-1,2,3,6-tetrahydropyridazin e 1 and 1,2-dicarbethoxY-1,2,3,4-tetrahydropyridazine 2 have been hydr oformylated and hydrocarbethoxylated in the presence of some well know n cobalt, rhodium, palladium and platinum catalysts. The hydroformylat ion reaction can be tuned by a suitable choice of the catalyst precurs or and reaction conditions, thus allowing the synthesis with high sele ctivity of one of the two possible isomeric aldehydes. The carbonylati on reaction is less synthetically useful, since it shows low activity and unsatisfactory chemo- and regio-selectivity. However, the ester 1, 2,4-tricarbethoxyhexahydropyridazine 10 can be prepared in good yield from olefin 1 by using the complex [PdCl2(PPh3)2] as the catalyst prec ursor.