Oxidative aryl-aryl, aryl-benzyl coupling of lignans-reactions of phyllanthin and haloderivatives with TTFA, DDQ, Li/THF)))): Synthesis of dibenzocyclooctadiene system and phyltetralin

Article abstract of DOI:10.1016/S0040-4020(01)91020-8

Treatment of phyllanthin (1) with TTFA in TFA gives dibenzocyclooctadiene (2) and phyltetralin (3). Treatment of (1) with DDQ in TFA also affords (2) while with DDQ in acetic acid gives 1-phenylnaphthalenic lignan (4). Synthesis of halophyllanthins (5,6,7) and its Ullmann reaction in ultrasonic condition affords reductive dehalogenated product (1) instead of (2). Treatment of (1) with POCl₃ in TCA gives (+) 3,4-diveratryltetrahydrofuran (8) and its conversion to (9) also reported. Treatment of (5) with TTFA/TFA gives (9).