Stereospecific Pd-Catalyzed Intermolecular C(sp3)-C(sp) Cross-Coupling of Diarylmethyl Carbonates and Terminal Alkynes Under Base-Free Conditions

Modular and Selective Access to Functionalized Alkynes and Allenes via the Intermediacy of Propargylic Acetates

We report an efficient one-pot, two-step procedure for the modular synthesis of α-difunctionalized alkynes and trisubstituted allenes by sequential cross-coupling of benzal gem-diacetates with organozinc or -copper reagents in the absence of external transition metals. The intermediacy of propargylic acetates enables the divergent and selective synthesis of these valuable products. This method features its readily accessible substrates, relatively mild conditions, wide scope, and scalability in practical synthesis.

Palladium-Catalyzed Cross-Coupling Reaction of Diarylmethanol Derivatives with Diborylmethane

A palladium-catalyzed cross-coupling reaction of diarylmethanol derivatives with diborylmethane has been developed. The reaction proceeds chemoselectively to deliver the corresponding homobenzylic boronates in good yields.

Reductant‐Free Cross‐Electrophile Synthesis of Di(hetero)arylmethanes by Palladium‐Catalyzed Desulfinative C−C Coupling

An efficient Pd‐catalyzed one‐pot desulfinative cross‐coupling to access medicinally relevant di(hetero)arylmethanes is reported. The method is reductant‐free, and involves a sulfinate transfer reagent and a Pd‐catalyst mediating the union of two electrophilic coupling partners; a (hetero)aryl halide and a benzyl halide. We establish for the first time that benzyl sulfinates, generated in situ, undergo efficient Pd‐catalyzed desulfinative cross‐coupling with (hetero)aryl halides to generate di(hetero)arylmethanes. The reaction can be extended to benzylic pseudohalides derived from benzyl alcohols. The reactions are straightforward to perform and scalable, and all reaction components are commercially available.

Divergent Synthesis of Isonitriles and Nitriles by Palladium-Catalyzed Benzylic Substitution with TMSCN

Ligand-controlled palladium-catalyzed divergent synthesis of isonitriles and nitriles from benzylic carbonates and TMSCN has been developed. The BINAP- or DPEphos-ligated palladium catalyst selectively provides the corresponding benzylic isonitriles, whereas their regioisomers, benzylic nitriles, are formed exclusively under phosphine ligand-free conditions. Mechanistic studies reveal that isonitrile is the primary product under both conditions, but it is isomerized into nitrile in the absence of ancillary phosphine ligands.

Ruthenium-catalyzed benzylic substitution of benzyl esters with stabilized carbon nucleophiles

We have accomplished the ruthenium-catalyzed benzylic substitution of benzyl esters with a stabilized carbon nucleophile. A [Cp*RuCl2]2/picolinic acid catalyst system promoted the reaction of 2-naphthylmethyl-2,3,4,5,6-pentafluorobenzoates with a series of stabilized carbon nucleophiles such as malonates, β-ketoesters, and diketones to give the corresponding benzylic alkylation products in moderate to high yields. We proposed a plausible reaction mechanism that could involve a (π-benzyl)ruthenium intermediate.

Redox deracemization of diarylmethyl alkynes

A highly effective one-pot redox deracemization of diarylmethyl alkynes has been disclosed.

Palladium-Catalyzed Asymmetric Benzylic Substitution of Secondary Benzyl Carbonates with Nitrogen and Oxygen Nucleophiles

A Pd/(R)-BINAP-catalyzed asymmetric benzylic substitution of secondary benzyl carbonates with amides and amines proceeds to form the corresponding optically active benzylamines in good yields with a high enantiomeric ratio. The reaction occurs in a dynamic kinetic asymmetric transformation (DYKAT) manner. Additionally, the asymmetric Pd catalysis can also be applicable to phenol nucleophiles, thus delivering chiral ethers with acceptable yields and enantioselectivity.