Cobalt-catalyzed multisubstituted allylation of the chelation-assisted C-H bond of (hetero)arenes with cyclopropenes

Temperature-Dependent Divergent Cyclopentadiene Synthesis through Cobalt-Catalyzed C-C Activation of Cyclopropenes

We report a temperature-dependent divergent approach to synthesize multisubstituted cyclopentadienes through cobalt-catalyzed carbon-carbon (C-C) bond activation of cyclopropenes and ring expansion with internal alkynes. By employing different heating procedures, two cyclopentadiene substitution isomers were efficiently and selectively constructed. This reaction does not require preactivation of the metal catalyst or additional reducing reagents. Preliminary mechanistic investigations suggest that the key steps are oxidative addition of the cyclopropene to cobalt catalyst, followed by alkyne insertion and 1,5-ester shift.

Co(III)-Catalyzed C6-Selective C-H Activation/Pyridine Migration of 2-Pyridones with Propiolates

A versatile Co(III)-catalyzed C6-selective C-H activation/pyridine migration of 2-pyridones with available propiolates as coupling partners was demonstrated. This method features high atom economy, excellent regioselectivity, and good functional group tolerance by employing an inexpensive Co(III) catalyst under mild reaction conditions. Moreover, gram-scale synthesis and late-stage modifications of pharmaceuticals were performed to prove the effectiveness of these synthetic approaches.

Diastereoselective Hydroacylation of Cyclopropenes by Visible-Light Photocatalysis

An efficient and general strategy for the hydroacylation of cyclopropene is disclosed for synthesizing various 2-acylcyclopropane derivatives under mild reaction conditions. High functional group tolerance of this protocol features a novel route to access a divergent synthesis of acylated cyclopropane in a diastereoselective manner by photoinduced decarboxylation of α-ketoacid followed by acyl radical addition to cyclopropene. Additionally, the regioselective addition of acyl radical at the least substituted olefinic carbon center with trans-selective fashion makes this protocol more appealing toward natural product development.

Catalytic regio- and stereoselective silicon–carbon bond formations on unsymmetric gem-difluorocyclopropenes by capture of silyl metal species

A highly regioselective silylation of unsymmetric gem-difluorocyclopropenes was achieved by the capture of in-situ formed silyl metal intermediates, which gave structurally diverse silyldifluorocyclopropanes with good yields and stereoselectivity.

Rhodium-Catalyzed Dearomative Rearrangement of 2-Oxypyridines with Cyclopropenes: Access to N-Alkylated 2-Pyridones

A rhodium-catalyzed dearomative O-to-N rearrangement reaction of 2-oxypyridines has been developed by using cyclopropenes as the carbene precursors. This protocol features broad substrate scope and mild reaction conditions, providing a...

Cp*CoIII-catalyzed C2-alkylation of indole derivatives with substituted cyclopropanols

A general and efficient Cp*CoIII-catalyzed C2-alkylation of N-pyridylindoles has been achieved utilizing cyclopropanols as an alkylating reagent.