This paper presents a synthesis of ent-alantrypinone (ent-6), the enantiomer of a natural product produced by the fungus Penicillium thymicola. The synthesis revolves around the Li [Me3AlSPh]-promoted isomerization of iminobenzoxazine 33 to quinazolinone 34, an N- acyliminium ion cyclization that converts enamide 9 to bridged indole 35, and rearrangement of 35 to oxindole ent-6. Ancillary chemistry that involves thermal ...
