PALLADIUM-CATALYZED GENERATION OF O-ALLYLIC URETHANES AND CARBONATES FROM AMINES/ALCOHOLS, CARBON-DIOXIDE, AND ALLYLIC CHLORIDES

Addition of preformed carbamate anions RR'NHCO2-(+H base), generated from various primary and secondary amines and carbon dioxide, to THF solutions of allylic chlorides under 80-100 psig carbon dioxide at room temperature (or 30-degrees-C) containing a palladium/phosphine catalyst gave high yields and high selectivities of O-allylic urethanes (66-100%). The choice of added base in the generation of carbamate was found to be critical for high yields of O-allylic products. The use of a guanidine (N-cyclohexyl-N',N',N'',N''-tetramethylguanidine) or amidine (1,8-diazabicyclo[5.4.0]undec-7-ene) base is optimal for this system. Use of a diamine (N,N'-dimethylhexamethylenediamine), carbon dioxide, 2 equiv of base, and 1,4-dichloro-2-butene with added palladium/phosphine catalyst gave polyurethane with M(n) = 5400 and M(w) = 8900. Substitution of benzyl alcohol for the amines in this catalytic process gave an 88% yield of benzyl allyl carbonate. The rate of appearance of benzylethylcarbamate from benzylethyl amine, carbon dioxide, and allyl chloride catalyzed by a palladium/phosphine complex was determined for four concentrations of catalyst and indicated a first-order dependence on catalyst concentration with a turnover number of 2600 moles per hour per mole of catalyst.