title: Gold(I)/(III)-Catalyzed Synthesis of Cyclic Ethers; Valency-Controlled Cyclization Modes.
abstract: Strategic use of oxophilic (hard) gold(III) and π-philic (soft) gold(I) catalysts provides access to two types of cyclic ethers from propargylic alcohols. Thus, heating propargylic alcohols with an oxophilic gold(III) catalyst (AuBr3) results in cyclization to afford cyclic ethers bearing an acetylenic moiety, due to coordination of gold(III) to the oxygen of the propargylic hydroxyl group. On the other hand, propargylic alcohols with a π-philic gold(I) catalyst (Ph3PAuNTf2) induces Meyer-Schuster rearrangement to afford α,β-unsaturated ketones, which undergo gold(III)-catalyzed intramolecular oxa-Michael addition to afford cyclic ethers bearing a carbonyl group, due to coordination of gold(III) to the oxygen of the carbonyl group.
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Morita
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Yasuda
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Shibata
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Ban
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Okamoto
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Tamura
mesh_terms: D002384:Catalysis; D003500:Cyclization; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D004988:Ethers, Cyclic; D006046:Gold