New Chemical Processes with Bismuth(III) Salts

This book describes several new processes using bismuth(III) reagents and catalysts, with application to steroid chemistry. Two processes for the nucleophilic ring opening of epoxysteroids are presented: one describes the Ritter reaction to afford vic-N-acylamino-hydroxy compounds, whereas the other show that bismuth(III) salts can act both as nucleophiles and reaction promoters, to obtain -substituted-hydroxy steroids. The bismuth(III) salt-catalyzed rearrangement of epoxysteroids is described as a strategy to obtain steroids bearing abnormal ring fusions, inverted configuration at bridgehead stereocenters and methyl groups out of their typical positions, leading to olefinic 19-nor, 18,19-dinor- or 18-norsteroids. The bismuth(III) triflate-catalyzed cleavage of the C17-side chain of corticosteroid allows the easy preparation of highly functionalized 17-ketosteroids. Moreover, full structural elucidation of all the obtained compounds is provided and largely discussed. A general introduction provides the background knowledge to this work. The concept of pharmaceutical green chemistry is discussed in the light of its integration with chemical process within pharmaceutical chemistry.