Novel process for the preparation of 13.beta.-alkyl-4-gonene-3,17-diones of the formula ##STR1## wherein R.sub.1 is methyl or ethyl, consists of REACTING A 7A.beta.-ALKYL,5,6,7,7A-TETRAHYDROINDANE-1,5-DIONE WITH FORMALDEHYDE AND AN ARYLSULFINIC ACID OR AN ADDUCT OF FORMALDEHYDE AND ARYLSULFINIC ACID TO PRODUCE A TETRAHYDROINDANE DERIVATIVE; Hydrogenating the tetrahydroindane derivative with hydrogen in the presence of a palladium-, platinum-, or rhodium-containing hydrogenation catalyst to produce a perhydroindane derivative; Condensing the perhydroindane derivative in the presence of a proton-accepting agent with a 7,7-alkylenedioxy-3-oxooctanoic acid ester; Treating the product obtained with a strong aqueous base and then heating the product in an inert solvent to produce a 4,5-secosteroid; Hydrogenating the 4,5-secosteroid in the presence of a palladium-, platinum-, rhodium-, or nickel-containing hydrogenation catalyst; and Hydrolyzing and cyclizing the hydrogenated 4,5-secosteroid by treatment with a strong acid.
The tricyclic intermediate ##STR1## is prepared in a three step sequence from the bicyclic intermediate ##STR2## The key step of this process involves the addition of a Grignard reagent to a mixed anhydride. Tricyclic compound of formula (I) may be readily converted by known methods to valuable steroids.
