B-Ring Contraction in Steroids via Benzilic Acid Rearrangement
Philipp Heretsch provides access to a rare sub-class of steroids via benzilic acid rearrangement.
Access to 5(6→7)abeo-Steroids through Benzilic Acid Rearrangement of i-Steroids: F. Noack, B. Hartmayer, P. Heretsch
Synthesis 2018, 50, 809–820
5(6→7)abeo-Steroids constitute a small and quite rare sub-class of steroids characterized by the presence of a 5-membered B-ring, in contrast with the 6-membered B-ring featured by more common cholesterol-type steroids. Recently, the group of Professor Philipp Heretsch from the Free University of Berlin reported one of the first methods for accessing this unusual type of steroids from cholesterol-derived steroids, using a ‘benzilic acid rearrangement’, namely a rearrangement of a B-ring diketone intermediate, mediated in this case by a Cu(I) cation.