PREPARATION OF 3α-FLUORO- AND 3β-FLUORO DERIVATIVES OF 5α-ANDROST-16-ENES AND ANDROSTA-5,16-DIENES

ABSTRACT

n-Perfluorobutanesulfonyl fluoride, in the presence of DBU, is shown to be a convenient and satisfactory reagent for the preparation of a variety of unsaturated 3-fluorosteroids of defined stereochemistry. 3-Fluoro-16,17-dehydrosteroids are reported for the first time. Fluorodehydroxylation proceeded with retention of configuration for 5,6,16,17-tetradehydro-3β-sterols, but with inversion for their 3α-analogues, as it did for several 16,17-dehydrosterols.

Keywords:

• 3-Fluorosteroids
• Fluorodehydroxylation
• n-Perfluorobutanesulfonyl fluoride

ACKNOWLEDGMENTS

We acknowledge generous support from Quest International. We are grateful to Mike Cocksedge of the ULIRS for obtaining mass spectra.