A Total Synthesis of (±)-Tacamonine (Pseudovincamone I) through Radical Cyclization

The radical cyclization of the bromo ester (11), prepared from 2-hydroxymethylbutan-1-ol (7), giving the diastereoisomeric mixture of lactones (12) was examined under various conditions. Treatment of the bromo ester (17), derived from 7, with tris(trimethylsilyl)silane in the presence of 2,2-azoisobutyronitrile provided the epimeric mixture of lactams (18), convertible to (±)-tacamonine (pseudovincamone I) (1) in three steps