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Dieckmann condensation of dimethyl 2,3-seco-5a-pregnan-20-one-2,3-dioate (la) gave an 84% yield of 3a-carbomethoxy-A-nor-5a-pregnane-2,20-dione (lie). Alkylation of lie with methyl iodide gave a 91% yield of a 1:1 mixture of the 3aand 3/3-methyl /3-keto esters IId,e. Hydrolysis and decarboxylation of the mixture gave a mixture of 3aand 3/3-methyl-A-nor-5a-pregnane-2,20-diones (IIf,g) (80-85% 3a-methyl isomer). The same sequence of reactions in the cholestane series gave the /3-keto ester Ilia in 70% yield, and alkylation of this with methyl iodide gave a mixture of the 3-methyl epimers IIIb,c in 60% yield. Hydrolysis and decarboxylation gave a 70% yield of 3a-methyl-A-nor-5a-cholestane-2-one (Hid).In a previous study1 the application of the Dieckmann