An oxidative intramolecular phenolic coupling reaction for the synthesis of amaryllidaceae alkaloids using a hypervalent iodine(III) reagent

The oxidative intramolecular phenolic coupling reaction of norbelladine derivatives (1) was investigated with the aim of preparing amaryllidaceae alkaloids. Spirodienone compounds (2), which are intermediates for the synthesis of an amaryllidaceae alkaloid, (+)-maritidine, or phenol ether derivatives containing the 5,6,7,8-tetrahydrobenzazocine systems (9), were selectively obtained by the reaction of 1 and the hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA). Both p-p' coupling (11) and p-o' coupling spirodienone compounds (12) were obtained by the reaction of phenol derivatives having an alkoxy group at the C-3' position (10) with PIFA.