Addition of ethyl urethane to olefins: A new approach to the synthesis of aliphatic carbamates

Several different palladium-based catalytic systems have been investigated for the addition of urethane (NH(2)COOEt) to olefins. A catalytic system based on PdCl2(CH3CN)(2)/CuCl/O-2 gave good results only in the case of the activated olefin methyl acrylate. Catalytic systems of the type Pd(acac)(2)/phosphorus ligand/acid, previously used to catalyse the telomerisation of conjugated olefins with amines, gave the desired adduct, together with the product of addition of one molecule of urethane and two molecules of diolefin, in the case of isoprene and 2,3-dimethylbutadiene. The main by-products were the dimers of the diolefin, whereas the selectivity in urethane appears to be high. In no case could the addition of urethane to an unactivated non-conjugated olefin be achieved.