- Ruthenium(II) porphyrin catalyzed formation of (Z)-4-alkyloxycarbonyl-methylidene-1,3-dioxolanes from γ-alkoxy-γ-diazo-β-ketoesters
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(equation presented) R1 = aryl, allyl R2= methyl, 2,4-dimethyl-3-pentyl and (-)-menthyl Ruthenum(II) porphyrins and dirhodium(II) acetate catalyze cyclization of γ-alkoxy-α-diazo-β-ketoesters to (Z)-4-(alkyloxycarbonylmethylidene)-1,3-dioxolanes selectively (ca. 68% yield) with no formation of 3(2H)-furanones. Reacting a diazo ketoester with [RuII(TTP)(CO)] [H2TTP = 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.
- Zheng, Shi-Long,Yu, Wing-Yiu,Che, Chi-Ming
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p. 889 - 892
(2007/10/03)
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