A Stereocontrolled Synthesis of (±)-Xenovenine via a Scandium(III)-Catalyzed Internal Aminodiene Bicyclization Terminated by a 2-(5-Ethyl-2-thienyl)ethenyl Group

A highly diastereoselective binary hydroamination of a 5-amino-1,8-diene containing a 2-(5-ethyl-2-thienyl)ethenyl terminator has been utilized in an efficient synthesis of (±)-xenovenine (1). A pronounced rate enhancement was observed for cyclization onto the 2-(heteroaromatic)ethenyl group in comparison to a simple 1,2-disubstituted alkene.