Scientia Sinica

52 SCIENTIA SINICA Vol, V

COOH C= OCH, (CH) Ma ? Ne oS 1. NaOCH, ( YY ee ) [OCH 2. CHgl JN/\/ L\/\/ Con » OCHsg d-Acid XIII aN, CH CH 20): ox po /\-cZocu, | | CT OCH Zo Z. | ee e75an aN at ee Oe Crs = OY Yon 2 : S | YEON) Ni VN OCH; OCH; . I-Keto ester ; _ Hydroxy ester XV XVI

In the above series of reactions, the chief point of interest is that from the dimethyl ester of /-y-(6-methoxy-2-carboxy-1,2,3,4-tetrahydro-l-naphthyl)butyric acid (X), after Dieckmann reaction and methylation, a mixture of the diastereoisomers of d-1-keto-2-methyl-2-carbomethoxy-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene (XI) was obtained. In the same way, from the dimethyl ester of d-y-(6-methoxy-2-carboxy-1,2,3,4-tetrahydro-1-naphthyl)butyric acid (XIV), after Dieckmann reaction and methylation, a mixture of the diastereoisomeric /-keto esters (XV) was obtained (compare with (2) ).

By use of Reformatsky reaction between the acetone-petroleum ether least soluble diastereoisomeric d-keto ester (XI) and methyl bromoacetate, methyl d-\-hydroxy-2-methyl-2-carbomethoxy-7-methoxy-l, 2, 3, 4, 9, 10, 11, 12-octahydrophenanthrene-l-acetate (XII) was obtained. In the same way, from acetonepetroleum ether least soluble diastereoisomeric /-keto ester (XV) and methyl bromoacetate, methyl /-1-hydroxy-2-methyl-2-carbomethoxy-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene-l-acetate (XVI) was obtained. At the start of our work, our primary aim was to isolate the pure d~ and /-keto esters from their respective diastereoisomeric mixtures and then to prepare the corresponding hydroxy ester by means of Reformatsky reaction between each of the pure diastereoisomeric keto esters and methyl bromoacetate. From each of the hydroxy esters, according to the series of reactions employed by Bachmann and coworkers in the synthesis of estrone A from 1-keto-2-methyl-2carbomethoxy-7-methoxy-l, 2, 3, 4, 9, 10-hexahydrophenanthrene, each of the optically active estrones could be obtained. But before the completion of our work, Miescher and coworkers"! published their work on the synthesis of d/estrone from one of the racemic 1-keto-2-methyl-2-carbomethoxy-7-methoxy-