SELECTIVE HYDROFORMYLATION OF OPEN-CHAIN CONJUGATED DIENES PROMOTED BY MESITYLENE-SOLVATED RHODIUM ATOMS TO GIVE BETA,GAMMA-UNSATURATED MONOALDEHYDES

The hydroformylation of 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3- pentadiene using rhodium vapour-mesitylene cocondesates as a catalytic precursor is reported. The reaction gives beta,gamma-unsaturated mono aldehydes with high chemoselectivity and regioselectivity. eta(3)-Bute nyl complexes, derived from the addition of Rh-H species to the conjug ated double-bound system, are likely to be intermediates, as suggested by deuterioformylation experiments.