Weixing Chang

Copper-Catalyzed Cascade Reaction via Intramolecular Hydroamination Cyclization of Homopropargylic Amines and Intermolecular Povarov Reaction with Imines

A new one-pot cascade reaction of homopropargylic amines with simple imines is developed in the presence of Cu(OTf)2 and affords a series of hexahydro-1H-pyrrolo[3,2-c]quinoline derivatives in good to high yields. This reaction proceeds through an intramolecular hydroamination cyclization of homopropargylic amine to generate a highly reactive dihydropyrrole intermediate in situ. It subsequently reacts with imine via an intermolecular inverse-electron-demand aza-Diels-Alder reaction and a 1,3-H shift to give the fused pyrroloquinoline structures, forming two new C-C bonds and one C-N bond and one N-H bond.

Povarov Reaction of Cycloiminium Formed in Situ via Hydroamination Cycloisomerization of Homopropargylic Amines with Electron-Rich Olefins

A new, one-pot cascade reaction of homopropargylic amines with electron-rich olefins is developed in the presence of Cu(OTf)2 and affords a series of octahydrofuro[3,2-c]pyrrolo[1,2-a]quinoline derivatives in yields of 38-80%. This reaction proceeds through an intramolecular hydroamination cyclization of homopropargylic amine to generate a highly reactive cycloenamine intermediate in situ that subsequently isomerizes to the cycloiminium cation followed by the Povarov-type reaction with dihydrofuran, dihydropyran, or dihydropyrrole. Notably, the Al2O3 additive plays a key role for the effective inhibition of competitive self-dimerization of homoproargylic amines.

Cu(OAc)2/TEMPO Cooperative Promoted Hydroamination Cyclization and Oxidative Dehydrogenation Cascade Reaction of Homopropargylic Amines

A novel and efficient Cu(OAc)2 -catalyzed hydroamination cyclization and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidative dehydrogenation cascade reaction of homopropargylic amines has been developed. A library of 1,2-disubstituted pyrrole derivatives were obtained in good-to-high yields in one pot with no step-by-step feeding process. This reaction involved TEMPO playing dual roles as both an oxidative dehydrogenation reagent and a ligand. An insight into the reaction mechanism was obtained by using several analytical determination methods.

Mutual Cooperation in the Formal Allyl Alcohol Nucleophilic Substitution and Hydration of Alkynes for the Construction of γ‐Substituted Ketones

Mutual cooperation in the formal allyl alcohol nucleophilic substitution reaction and hydration of an alkyne has been utilized in the presence of a gold catalyst to give a series of γ-functionalized ketones with high to excellent yields. This reaction actually involved an intramolecular O-H insertion cyclization of an alkyne to form the dihydrofuran intermediate, which was followed by the nucleophilic addition ring-opening of a dihydrofuran to give the target compound.

Copper Promoted Regio‐ and Stereoselective Aminochlorination of Alkynes and Alkenes with NFSI

A simple and rapid copper-promoted aminochlorination of unactivated alkynes and alkenes with N-fluorobenzenesulfonimide (NFSI) was developed. Two series of chloroenamines and chloroamines were obtained in good to high yields. The chlorinated enamines could be obtained in a single E configuration. This reaction involved a radical process and the CuCl2 acted as the Cl source and NFSI as the N source.

Morphological studies on Sn-O coordination driving self-assembly of well-defined organotin-containing block copolymers

A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer (RAFT) method and characterized by the gel-permeation chromatography (GPC) and 1H-NMR. And the self-assemblies of these block copolymers with various chain length ratios in the different concentrations in CHCl3 were stable according to the results of DLS and TEM. Additionally, it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.

Ag(I)-catalyzed solvent-free CO2 capture with homopropargylic amines: an efficient access to 1,3-oxazinan-2-ones

An efficient solvent-free CO2 capture and transformation method was developed through using homopropargylic amines in the presence of AgOAc and DBU, and a series of 1,3-oxazinan-2-ones was obtained in excellent yields.