title: Ruthenium(II) porphyrin catalyzed formation of (Z)-4-alkyloxycarbonyl- methylidene-1,3-dioxolanes from gamma-alkoxy-alpha-diazo-beta-ketoesters.
abstract: [reaction: see text] Ruthenum(II) porphyrins and dirhodium(II) acetate catalyze cyclization of gamma-alkoxy-alpha-diazo-beta-ketoesters to (Z)-4-(alkyloxycarbonylmethylidene)-1,3-dioxolanes selectively (ca. 68% yield) with no formation of 3(2H)-furanones. Reacting a diazo ketoester with [Ru(II)(TTP)(CO)] [H(2)TTP = meso-tetrakis(p-tolyl) porphyrin] in toluene afforded a ruthenium carbenoid complex, which has been isolated and spectroscopically characterized. A mechanism involving hydrogen atom migration from the C-H bond to the ruthenium carbenoid is proposed.
authors.affiliation: Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Shi-Long
authors.initials: SL
authors.lastname: Zheng
authors.forename: Wing-Yiu
authors.initials: WY
authors.lastname: Yu
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Che