1.
J Org Chem
; 61(20): 6974-6979, 1996 Oct 04.
Article
in English
| MEDLINE
| ID: mdl-11667595
ABSTRACT
An acyl iminium ion-initiated tandem cyclization gave an unexpected dienone product, a seco-azasteroid (2). The factors governing the formation of 2 were investigated in an attempt to optimize its formation. The reaction was applied to a more elaborate system, resulting in the synthesis of the full steroid skeleton of 13-azaandrosta-1,4-diene-3,17-dione (3), which contains the unusual substitution of a chlorine atom for the axial 19-methyl.