Studies of the slowing of the dienone-phenol rearrangement of a steroidal 1,4-dien-3-one by the introduction of an 11-keto group.

Article abstract of DOI:10.1016/0039-128X(89)90059-7

It has been shown previously that steroidal 11-keto-1,4-dien-3-ones undergo dienone-phenol rearrangement significantly more slowly than their 11-deoxy-, or 11 beta-hydroxy- and 11-acetoxy analogs. We have tested the explanations suggested for this, and are able to reject most of them. There remains the probability that the 11-keto group reduces the migrating ability of the adjacent atom, C-9, which frequently migrates in steroidal rearrangements.