Short, Enantioselective Total Synthesis of Sceptrin and Ageliferin by Programmed Oxaquadricyclane Fragmentation

Absolutely without auxiliaries: The enantioselective syntheses of both enantiomers of the dimeric pyrrole–imidazole alkaloids sceptrin and ageliferin have been achieved by a non-auxiliary-based route, which allows assignment of the absolute configuration of natural ageliferin. The “programming” of the oxaquadricyclane fragmentation leading to enantiopure tetrasubstituted cyclobutanes is the crucial step in the synthesis.