Torgov-Smith synthesis

In the first of these sequences, often called the Torgov-Smith synthesis, the initial step consists in condensation of a 2-alkyl-cyclopentane-l,3-dione with the allyl alcohol obtained from 6-methoxy-l-tetralone and vinylmagnesium chloride. Although this reaction at first sight resembles a classic SN displacement, the reaction is actually carried out with only a trace of base. 

The scheme used to prepare the direct 8-aza-analogue 21 of estrone bears at least formal similarity to the Torgov-Smith steroid total synthesis sequence. Acylation of the phenethylamine 9 with acryloyl chloride gives amide 16. Michael addition of dimethylamine followed by Bischler-Napieralski cyclodehydration gives the dihydroisoquinoline, 17. 

A new angular methylation procedure, at Cis, involving the Simmons-Smith reagent was discovered, thus extending the usefulness of the Smith-Torgov total synthesis of 19-norsteroids. The preparation and properties of 5,19-cyclosteroids was the subject of several studies.Interestingly enough, the Villsmeier reaction on enamines of 3-heto-A -steroids led to the 1,6-diformyl derivatives. ... 

Torgov-Smith steroid synthesis 23, 924 suppl. 26 Tosylamines... 

The relative simplicity of the structure of estranes compared with those of other classes of steroids has made this structural class an attractive target for work aimed at total synthesis from so-called coal tar starting materials. About half a dozen syntheses have been developed, one of which, the Smith-Torgov synthesis, is probably stiU used commercially. 

Modifications of the Smith-Torgov scheme for total synthesis of estranes provides access to oxaestrane (7-1) and also its derivatives, 7-2 and 7-3. 

Total Synthesis - A major effort vra.s devoted to developing and disproving the original Smith-Torgov reaction sequence leading to estrapentaenes of type XIII. 

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