Steroids, hydrogenation

Catalytic hydrogenation has been utilized extensively in steroid research, and the method has been found to be of great value for the selective and stereospecific reduction of various functional groups. A number of empirical correlations concerning selectivity and product stereochemistry compiled for steroid hydrogenations has been listed in a previous review. ... 

The effect of a hydroxyl group on the direction of steroid hydrogenation over other catalysts has not been investigated systematically. In the hydrogenation of the lljS-hydroxy compound (51) nearly equal amounts of the... 

Acknowledgements I wish to acknowledge the assistance of Drs. K. Heusler and E. Farkas and Professors C. Djerassi, H. B. Henbest, W. S. Johnson and S. Nishimura in providing data on their work on steroid hydrogenations prior to publication. 

In all these reactions, crystallographic studies demonstrated the crystal control responsible for formation of the observed products. Thus, the prereaction ketone oxygen-steroidal hydrogen distance is in all cases 3.4 0.5 A, the ketonic carbon-steroidal (to-be-attacked) carbon distance is of the order of 4 A, and the... 

Steric approach control, 67 Steric strains, 71 Steric strain control, 69 Steroid hydrogenation, 111 5/3-Stigmast-22-en-3-one, 130 Stigmasterol, 266 Sulfur dichloride, 459 Sulfur tetrafluoride, 459, 472 Sulfur tetrafluoride fluorination, 471 Surface catalysts, 157... 

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