Chemistry of α-oxoesters: a powerful tool for the synthesis of heterocycles.

By using tandem Ru-catalysis, internal alkynes can be coupled with aldehydes for the synthesis of β,γ-unsaturated ketones. The catalyst promotes alkyne transformations with high regioselectivity, with examples that include the differentiation of a methyl vs ethyl substituent on the alkyne. Mechanistic studies suggest that the regioselectivity results from a selective allene formation that is governed by allylic strain.

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Alkyne Hydroacylation: Switching Regioselectivity by Tandem Ruthenium Catalysis

1,2-Diketones were synthesized by the oxidation of corresponding alkynes using air as the oxidant under metal-free conditions upon irradiation of blue light. A cheap and readily available organic dye, eosin Y, was used as the photocatalyst. For various substituents on the aryl ring, the reaction proceeded smoothly to give the dicarbonylation products in moderate to good yields. Some oxidation-sensitive groups, such as formyl and the carbon–carbon double bond, were tolerated under the developed reaction conditions.

Synthesis of 1,2-Diketones via a Metal-Free, Visible-Light-Induced Aerobic Photooxidation of Alkynes.

Copper‐Catalysed Multicomponent Syntheses of Heterocycles

An efficient and concise Cu(OTf)2-catalyzed Friedel–Crafts alkylation/annulation cascade reaction of substituted indoles with 1,2-dicarbonyl-3-enes has been established. This reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of diverse 9H-pyrrolo[1,2-a]indoles bearing a carbonyl group.

Construction of 9H-Pyrrolo[1,2-a]indoles by a Copper-Catalyzed Friedel–Crafts Alkylation/Annulation Cascade Reaction

An efficient and concise protocol has been developed for the highly regio- and stereoselective synthesis of E-1,2-dicarbonyl-3-ene derivatives by a copper-promoted reaction of 1-alkynes with α-carbonyl aldehydes in the presence of morpholine. The products obtained are believed as the formal hydroacylation of the triple bond.

Xiaojie Li

Papers

CuBr-Promoted Formal Hydroacylation of 1-Alkynes with Glyoxal Derivatives: An Unexpected Synthesis of 1,2-Dicarbonyl-3-enes

Copper‐Catalyzed Multicomponent Amination/Alkynylative Cycloisomerization Cascade: Facile Access to Ferrocene‐Containing Indolizine Derivatives

CuBr‐Promoted Formal Hydroacylation of 1‐Alkynes with Glyoxal Derivatives: An Unexpected Synthesis of 1,2‐Dicarbonyl‐3‐enes.