reaction conditions. Thus, both y-lactones and &-lactones are obtained from unsaturated, a$-unsaturated esters: e.g. methyl crotonate, gives 72 % 8-valerolactone alongside 20 % P-methyl-y-butyrolactone, white with P,P-dimethylacrylic esters, because of complete isomerization, only P-methyl-&valerolactone is obtained in 88.5 % yield. 20 % 72 % 0 % 88.5 % The unsaturated starting materiaIs can be substituted by alkyl, alkylene, ethoxycarbonyl, and other functional groups. Alicyclic unsaturated carboxylic esters, such as cyclohexenyl, cyclopentenyl, and cycloheptenylisobutyric esters, lead to homologues of iridomyrmecin [ I]. Surprisingly, it was also possible to convert cinnamates into P-phenyl-y-butyrolactone in 34 % yield by employing stoichiometric amounts of the catalyst, although, according to various authors [2], these esters were not susceptible to hydroformylation reactions, giving hydrogenation products only. Publication withheld until now at the express wish of the authors. Received, June 13th. 1962 [Z 359/191 IE] [I J F. Korfe, J. Falbe, and A. Zschocke, Tetrahedron 6,201 (1 959). [2] M . Orchin, Advances in Catalysis 5, 385 (1953); R. Hasek, Organic Chemical Bulletin, 27 (1955) -published by theResearch Laboratories of the Eastman Company.