title: Palladium enolate umpolung: cyclative diacetoxylation of alkynyl cyclohexadienones promoted by a Pd/SPRIX catalyst.
abstract: A novel palladium-catalyzed reaction involving an unusual nucleophilic attack on a palladium enolate was developed using a spiro-bis(isoxazoline) (SPRIX) ligand. Treatment of alkynyl cyclohexadienone substrates with a Pd/SPRIX catalyst in acetic acid under an oxygen atmosphere furnished diacetoxylated benzofuranone derivatives in good yields. This cyclative diacetoxylation proceeded enantioselectively in the presence of an optically pure SPRIX ligand.
authors.affiliation: The Institute of Scientific and Industrial Research (ISIR), Osaka University, Mihogaoka, Ibaraki-shi, Osaka 567-0047 (Japan).
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takenaka
authors.forename: Suman C
authors.initials: SC
authors.lastname: Mohanta
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sasai
keywords: cyclization; enyne; palladium; spiro compounds; umpolung