Synthesis of an Azasteroid Using an Acyl Iminium Ion-Initiated Tandem Cyclization.
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.
Romero
Arthur G.
AG
Structural, Analytical, and Medicinal Chemistry, Pharmacia & Upjohn, Kalamazoo, Michigan, 49001.
Leiby
Jeffrey A.
JA
Mizsak
Stephen A.
SA