Various total syntheses are described, of (-j)-cestrone methyl ether and five of its stereoisomers, ( j-)-D-homo-estrone methyl ether, (&)-D-homoestradiol methyl ether, ( f ) -equilenin methyl ether, ( -J-)-D-homoequilenin methyl ether, ( & ) -isoequilenin, and related compounds. Preliminary accounts have already been given of some of this work. CESTRONE has been synthesised by a number of routes,lT7 three of which have been reported in preliminary form by us1 All are highly stereoselective throughout, the most efficient lb giving (&)-cestrone methyl ether in 18% overall yield from 3-m-methoxyphenylpropyl bromide, and, with minor modifications, providing syntheses of (&)equilenin methyl ether, (&)-isoequilenin, and five of the seven stereoisomers of (&)-cestrone methyl ether.General PZan.-The syntheses are all derived from the initial concept of preparing a seco-cestratetraene of type (3) and converting it into the corresponding seco-cestratriene (4) and thence, through a cyclodehydration reaction involving the %oxo-group, into estrone methyl ether (6). Discoveries made during the reduction practice opened other avenues to estrone and a variety of estrogenic steroids. The completed work constitutes a group of related syntheses the chief of which are shown in the annexed Scheme. The dione (3) has been elaborated by two routes. One involves the alkylation in the 4-position of the indanedione (2) with the 2-m-methoxyphenylethyl radical, the other a Mannich-Robinson type of ring extension of 2-methylcyclopentane-1,3-dione (1 1) with the vinyl * To whom enquiries concerning this paper should be addressed.tThe structural formulae containing one or more asymmetric carbon atoms depict one diastereoisomer but refer t o racemic compounds throughout. Each racemate is arbitrarily represented by the diastereoisomer having the 13-methyl group in the fl-configuration. Subsequently in the text the (&)-prefix will be omitted and the steroids and intermediates thereto are to beassumed t o be racemic unless stated otherwise.In the discussion, steroid nomenclature and numbering will be used t o describe tri-and tetra-cyclic compounds.

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