Formation of Tertiary Alcohols from the Rhodium-Catalyzed Reactions of Donor/Acceptor Carbenes with Esters.

Rhodium(II)-catalyzed reactions between isopropyl acetate and trichloroethyl aryldiazoacetates result in the formation of oxirane intermediates that ring open under the reaction conditions to form tertiary alcohols. When the reaction is catalyzed by the dirhodium tetrakis(triarylcyclopropanecarboxylate) complex, Rh( S-2-Cl,4-BrTPCP), the tertiary alcohols are formed with good asymmetric induction (80-88% ee).

Metal-Free C-H Functionalization of Alkanes by Aryldiazoacetates.

Thermally induced reactions of donor/acceptor diazo compounds generate carbene intermediates capable of C-H functionalization reactions of alkanes. A variety of C-H insertion products were obtained in moderate to good yields and in certain cases with good site selectivity, favoring the functionalization of the more highly substituted C-H bond.

Synthesis of Spiro Ketals, Orthoesters, and Orthocarbonates by CpRu-Catalyzed Decomposition of α-Diazo-β-ketoesters.

Reactions of α-diazo-β-ketoesters with cyclic ketones, lactones, and carbonates are reported. Thanks to the combined use of salt [CpRu(CH3CN)3][BArF] and 1,10-phenanthroline as catalyst for the diazo decomposition, effective and practical syntheses of spiro bicyclic ketals, orthoesters, and orthocarbonates are afforded.

Original reactivity of α-diazo-β- ketoesters catalyzed by CpRu complexes.

Using α-diazo-β-ketoesters as reagents and combinations of CpRu fragments and diimine ligands as catalysts, a series of original transformations have been obtained that can be rationalized by the formation of metal carbenes and metal-bound ylide intermediates. Interesting 1,3-dioxole, enol-acetal and 1,4-dioxene motifs are obtained directly when the reactive mixture is reacted in presence of aldehydes or ketones, THF and epoxides.

[CpRu]-catalyzed carbene insertions into epoxides: 1,4-dioxene synthesis through S(N)1-like chemistry with retention of configuration.

Rather than lead to the usual deoxygenation pathway, metal carbenes derived from α-diazo-β-ketoesters undergo three-atom insertions into epoxides using a combination of 1,10-phenanthroline and [CpRu(CH3CN)3][BAr(F)] as the catalyst. Original 1,4-dioxene motifs are obtained as single regio- and stereoisomers. A perfect syn stereochemistry (retention, e.