Jia Zheng

A Novel Straightforward Synthesis of 2,4-Disubstituted-1,3,5-triazines via Aerobic Copper-Catalyzed Cyclization of Amidines with DMF

A novel straightforward synthesis of both symmetrical and unsymmetrical 2,4-disubstituted-1,3,5-triazines via aerobic copper-catalyzed cyclization of amidines with DMF as a one-carbon synthon has been developed. The presented method allows synthesizing the products that are currently inaccessible or challenging to prepare with the advantages of operational simplicity, broad substrate scope, and no need for prefunctionalized reagents, making it a highly practical approach to access various 2,4-disubstituted-1,3,5-triazines.

Palladium-Catalyzed Intermolecular Aerobic Annulation of o-Alkenylanilines and Alkynes for Quinoline Synthesis

A new approach to construct 2,3-disubstituted quinolines is described via Pd-catalyzed oxidative cyclization of o-vinylanilines and alkynes with molecular oxygen. This transformation is supposed to undergo intermolecular amination of alkyne, insertion of the olefin, and oxidative cleavage of C-C bond sequence.

Synthesis of Polysubstituted Pyrroles via Pd-Catalyzed Oxidative Alkene C–H Bond Arylation and Amination

A novel Pd(II)-catalyzed oxidative approach to construct polysubstituted pyrroles from N-homoallylicamines and arylboronic acids was developed. This transformation is supposed to proceed through cascade formation of C-C and C-N bonds via oxidative arylation of unactive alkenes, followed by intramolecular aza-Wacker cyclization.

Dual Role of H2O2 in Palladium-Catalyzed Dioxygenation of Terminal Alkenes

A palladium-catalyzed, environmentally friendly dioxygenation reaction of simple alkenes has been developed that enabled rapid assembly of valuable α-hydroxy ketones with high atom economy. Notably, control experiments and 18O isotope-labeling experiments established that H2O2 played a dominant dual role in this transformation.

Access to α‐Amino Acid Esters through Palladium‐Catalyzed Oxidative Amination of Vinyl Ethers with Hydrogen Peroxide as the Oxidant and Oxygen Source

A novel and convenient palladium catalytic system for the synthesis of α-amino acid esters from simple starting materials is reported. Hydrogen peroxide not only acts as the green oxidant, but also as the oxygen source. This strategy for the conversion of amines and vinyl ethers into highly functionalized and structurally diverse α-amino acid esters is characterized by the simplicity of the experimental procedure, mild reaction conditions, high atom economy, scalability, and practicability.

Palladium-Catalyzed Intermolecular Oxidative Cyclization of Allyltosylamides with AcOH: Assembly of 3-Pyrrolin-2-ones

The first example of Pd-catalyzed oxidative cyclization of allyltosylamides with acetic acid is reported. This transformation involved C-N/C-C bond formation and provided 3-pyrrolin-2-ones in a one-pot manner with easy-operation, excellent atom economy and good yields. Mechanistic studies indicate that the reaction proceeds through intermolecular aminopalladation, migratory insertion, reinsertion and β-hydride elimination processes.

Synthesis of 1,4-enyne-3-ones via palladium-catalyzed sequential decarboxylation and carbonylation of allyl alkynoates

Herein we describe a novel protocol for the rapid assembly of 1,4-enyne-3-ones from isocyanides and 1,6-enyne. During this process, two different types of C–C bonds were formed on the same isocyanide carbon atom via sequential decarboxylation, insertion of isocyanide, and reductive elimination. Moreover, this approach shows advantages of mild reaction conditions and excellent functional group compatibility.

B2pin2-Mediated Palladium-Catalyzed Diacetoxylation of Aryl Alkenes with O2 as Oxygen Source and Sole Oxidant

A novel palladium-catalyzed alkene diacetoxylation with dioxygen (O2) as both the sole oxidant and oxygen source is developed, which was identified by 18O-isotope labeling studies. Control experiments suggested that bis(pinacolato)diboron (B2pin2) played a dominant intermediary role in the formation of a C-O bond. This method performed good functional group tolerance with moderate to excellent yields, which could be successfully applied to the late-stage modification of natural products. Furthermore, an atmospheric pressure of dioxygen enhances the practicability of the protocol.