CpRuCl-Catalyzed Formal Intermolecular Cyclotrimerization of Three Unsymmetrical Alkynes through a Boron Temporary Tether:  Regioselective Four-Component Coupling Synthesis of Phthalides

• Published in: Journal of the American Chemical Society Vol. 127; no. 26; pp. 9625 - 9631
• Main Authors: Yamamoto, Yoshihiko, Ishii, Jun-ichi, Nishiyama, Hisao, Itoh, Kenji
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 06.07.2005; Amer Chemical Soc
• Subjects: Chemical reactivity; Chemistry; Chemistry, Multidisciplinary; Exact sciences and technology; Organic chemistry; Physical Sciences; Reactivity and mechanisms; Science & Technology; BENZENE-DERIVATIVES; DIELS-ALDER REACTIONS; ASYMMETRIC 1,4-ADDITION; PALLADIUM-CATALYZED CARBONYLATION; METALATIVE REPPE REACTION; COBALTACYCLOPENTADIENE COMPLEXES; ALPHA,BETA-UNSATURATED CARBONYL-COMPOUNDS; ARYLNAPHTHALENE LIGNANS; ARYLBORONIC ACIDS; ORIENTED ORGANIC-SYNTHESIS; Catalytic reaction; Acetylenic compound; Regioselectivity; Catalyst selectivity; Ruthenium Organic compounds; Transition metal Complexes; Complex catalyst; Experimental study; Organic boronate; Boron Organic compounds; Platinoid Complexes; Chloro complex; Cyclotrimerization; Catalyst activity
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja051377d

Highly substituted phthalides were efficiently synthesized by sequential Cp*RuCl-catalyzed cyclotrimerization of alkynylboronates, propargyl alcohols, and terminal alkynes and palladium(II)-catalyzed carbonylation of the resultant arylboronates. The intermediate arylboronate was isolated and unambiguously characterized by X-ray crystallography. The perfect regioselectivity of the ruthenium-catalyzed formal intermolecular cyclotrimerization was discussed on the basis of the density functional calculations of a boraruthenacycle intermediate