The synthesis of 6, 16α, 17α-trimethylpregna-4,6-diene-3,20-dione

Alkylated steroids. Part 1. 16α-Substituted 17α-methylpregnanes

“…In every case the course of the reaction was unaffected by the presence or absence of copper catalyst, confirming that conjugate addition took place exclusively. In contrast 16aphenyl-l7a-methylpregnenolone (19) could only be isolated in the absence of catalyst, whereas the corresponding 16a-benzyl derivative (21) required the catalyst for its formation in acceptable yield.…”