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.