RhH(CO)(triphenylphosphine)3 in toluene T=20°C; 2 h;

cesium carbonate supported on γ- alumina in toluene T=80°C; Michael addition; 6 h;

in tetrahydrofuran Stirring of mixt. at room temp. for 15 h.; Extg. (ether), washing of ext. (aq. HCL, H2O), drying (Na2SO4), evapn., chromy. (hexane-ethyl acetate), elem. anal.;

hydrogenchloride; tetrabutyl ammonium fluoride 1.) CH2Cl2, rt; 2.) CH2Cl2, rt, 5 h; 3.) ether, water; Yield given. Multistep reaction;