Syntheses via diphenylethane derivatives

Two methods of synthesizing estrogenolic acids start from Hagemann s ester (505), formed with a yield of 50% by condensing formaldehyde with 

According to another method [584-586], Hagemann s ester (505) was alkylated with m-methoxyphenethyl bromide and the resulting keto ester (508) was cyclized to the tricyclic ester (512). From the latter, by a combination in a different sequence of the reactions of angular alkylation, isomerization of the double bond and hydrogenation, seven of 

By condensing with acetoacetic ester not formaldehyde, as in the synthesis of (505), but jS-(2,5-dimethoxyphenyl)propionaldehyde (511) it is possible after decarboxylation to obtain a high yield of compound (514). From the latter,by Birch reduction, hydrolysis, and oxidation, the triketone (515) has been obtained the cyclization of this is accompanied by a shift of the double bond and leads to the tricyclic diketone (516), which is a model compound for the synthesis of 19-norsteroids [587]. 

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Syntheses via Diphenylethane Derivatives. Total syntheses of doisynolic acids, their 8-aza analogs, and numerous tricyclic ABC intermediates have been effected by this route (Schemes 48-51). 

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