Nickel-Catalyzed Regioselectivity-Switchable Hydroheteroarylation of Vinylarenes with Electron-Rich Heteroarenes.

We report the first example of a regioselectivity switch in the hydroheteroarylation of vinylarenes with electron-rich heteroarenes, including benzofurans, benzothiophenes, and indoles, using an expedient ligand-controlled strategy. In the presence of NaOtBu, Ni(IMesMe)[P(OEt)3]Br2 yields C2-alkylated heteroarenes with high branched selectivity, whereas the use of Ni(IPr*OMe)[P(OEt)3]Br2 favors the formation of the corresponding linear products. This robust method also provides easy access to a range of C2-alkylated electron-rich heteroarenes without employing directing groups.

Rare Earth Amide-Catalyzed Direct Thioesterification of Aldehydes with Thiols under Mild Conditions.

Direct thioesterification of aldehydes with thiols catalyzed by readily accessible rare earth/lithium amide RE[N(SiMe3)2]3(µ-Cl)Li(THF)3 is developed, which enables the preparation of a range of thioesters (31 examples) under room temperature and solvent-free conditions, without using any additive or external oxidant. This method provides a straightforward and atom-efficient approach for the thioester synthesis.

Ligand-Controlled Nickel-Catalyzed Tandem Isomerization/Regiodivergent Hydroheteroarylation of α-Alkenes with Heteroarenes.

We herein describe an accessible ligand-controlled nickel-catalyzed tandem isomerization/regiodivergent hydroheteroarylation of α-alkenes with a series of heteroarenes, wherein the NHC ligand of heteroleptic Ni(II) complexes of the type Ni(NHC)[P(OEt)3]Br2 displayed significant effects on regulation. In the presence of NaOtBu, Ni(IMes)[P(OEt)3]Br2 enables C═C bond isomerization of α-alkenes over up to four sp3 carbon atoms to afford branched products, while Ni(IPr*OMe)[P(OEt)3]Br2 greatly deactivates α-alkene isomerization and favors the formation of linear products.

Synthesis and characterization of rare earth/lithium complexes stabilized by ethylenediamine-bridged bis(phenolate) ligands and their activity in catalyzing amidation reactions.

Rare earth/lithium complexes stabilized by ethylenediamine-bridged bis(phenolate) ligands have been synthesized and characterized. In addition to five rare earth/lithium amides isolated as major complexes, two other rare earth/lithium complexes bearing two phenolate ligands were also isolated. The activities of rare earth/lithium amides in catalyzing the amidation of aldehydes and amines were studied, which revealed that the yttrium/lithium complex was highly active for a wide range of substrates, generating 58 examples of amides in 42-99% yields under mild conditions (i.e., room temperature, 3-hour reaction time, additive-free). More importantly, this is the first example of rare earth-based catalysts capable of catalyzing the amidation of primary aliphatic amines.