Cavit Uyanik

The stereochemistry of the Grignard reaction of steroidal 4,5-epoxy-3-ketones

The stereochemistry of the addition of methylmagnesium bromide to a steroidal 4,5-epoxy-3-ketone has been shown to be determined by the stereochemistry of the epoxide. The epoxidation to the corresponding 3-alkyl-3-hydroxy-4-enes by per-acid was determined by the stereochemistry of the allylic alcohol.

Ring A aromatic steroids in the pregnane series

4-Methylpregna-1,3,5(10)-trien-20-one and 4-methylpregna-1,3,5(10),16-tetraen-20-one have been obtained by a dienol: benzene type of rearrangement of 5α,6α-epoxypregnanes possessing a further double bond equivalent on ring A. The crystal structure of 4-methyl-19-norpregna-1,3,5(10)-trien-20-one is reported.

The chemistry of B-norsteroidal 6-ketones and their relatives

The preparation and reactions of B-norsteroidal 6-ketones and their relatives are reviewed in the context of the stability of the A/B and B/C ring junctions and the stereochemistry of the addition reactions to the carbonyl group. This review is a sequel to a previous article on the reactions of B-norsteroidal 4- and 5-enes.

Ethanolysis of steroidal epoxides catalysed by tetracyanoethylene

Ethanolysis of the epimeric androstane 4,5- and 5,6- epoxides catalysed by tetracyanoethylene is reported. In contrast to other reagents, these reactions involve the mild room temperature trans diaxial opening of the epoxides. The stereochemistry of three of the products was established by X-ray crystallography.