Ruthenium(II) porphyrin catalyzed formation of (Z)-4-alkyloxycarbonyl- methylidene-1,3-dioxolanes from gamma-alkoxy-alpha-diazo-beta-ketoesters

Shi-Long Zheng; Wing-Yiu Yu; Chi-Ming Che

doi:10.1021/ol010283f

Ruthenium(II) porphyrin catalyzed formation of (Z)-4-alkyloxycarbonyl- methylidene-1,3-dioxolanes from gamma-alkoxy-alpha-diazo-beta-ketoesters

Org Lett. 2002 Mar 21;4(6):889-92. doi: 10.1021/ol010283f.

Authors

Shi-Long Zheng¹, Wing-Yiu Yu, Chi-Ming Che

Affiliation

¹ 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.

PMID: 11893178
DOI: 10.1021/ol010283f

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.