title: Gold(I)-catalyzed asymmetric desymmetrization of meso-alkynyl diols and kinetic resolution of the corresponding DL-diols: effects of celite filtration and silver salts.
abstract: The asymmetric desymmetrization of meso-2-alkynylbenzenediols through the use of a combination of axially chiral diphosphine(AuCl)2 precatalysts and silver salt co-catalysts gave optically active isochromene compounds with high enantioselectivities in good yields. The corresponding DL-diol isomers underwent efficient kinetic resolution to give the cyclized isochromenes and recovered diols with high enantioselectivities under similar conditions. The high reactivity and selectivity in the desymmetrization of the meso-diols is independent of the combination of axially chiral diphosphine(AuCl)2 precatalyst and silver salt co-catalyst, whereas the corresponding tricarbonylchromium complexes of alkynylbenzenediols were affected by the combination of the diphosphine(AuCl)2 and silver salt. The reactivity was largely dependent on the nature of the gold(I) species.
authors: Kyoto Pharmaceutical University, Yamashina, Kyoto 607-8412 (Japan).
authors: Yumi
authors: Y
authors: Sota
authors: Masaaki
authors: M
authors: Yamamoto
authors: Masato
authors: M
authors: Murai
authors: Jun'ichi
authors: J
authors: Uenishi
authors: Motokazu
authors: M
authors: Uemura
mesh_terms: D002384:Catalysis; D003500:Cyclization; D005374:Filtration; D006046:Gold / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D015394:Molecular Structure; D012834:Silver / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D012834:Silver; D006046:Gold
keywords: asymmetric synthesis; desymmetrization; gold; kinetic resolution; silver