D-Norsteroids

The other three methods have not been studied extensively. The dimethyl-cadmium route has been used on a 17a-methyl-17 -carboxylic acid. ° The reaction of the acid amide with a Grignard reagent is described only in a Spanish patent,with a high yield claimed, and the methyllithium reaction has apparently been tried only on D-norsteroids. ... 

Photochemical Wolff rearrangement of 2-diazo-3-ketones, though not widely used as a source of A-norsteroids, is discussed in section V in connection with the mechanism of the important photochemical synthesis of D-norsteroids. Photochemical rearrangement of epoxy ketones is a source of A-nosteroids these rearrangements are discussed in chapter 13. Other photochemical routes to A-norsteroids are known." " ... 

During 1961-2 four independent groups almost simultaneously reported the first syntheses of D-norsteroids, based on the photolysis of 16-diazo-17-ketones. In a typical procedure. Cava and Moroz ° convert the 16-oximino-17-one (93) derived from estrone methyl ether (92) to the diazoketone (94)... 

A nonphotochemical method for the preparation of D-norsteroids involves the base-catalyzed pinacol rearrangement of a pregnane-16oc,17a-diol 16a-mesylate. ... 

This method was employed in the synthesis of 16-acyl-D-norsteroids (see Houben-Weyl, Vol. 4/4, pp 94-119) the product 7 was formed as a mixture of epimers in 50% yield.76... 

D-Norsteroids have provided a series of compounds especially appropriate for the examination of carbenium ion reactions of cyclobutanes of defined conformation. ... 

D-Norsteroids have been obtained by ring contraction of a-diazoketones A strikingly selective and remarkably smooth reaction gives 2-hydroxycyclobutanones from a-diketones by irradiation... 

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