Jingping Zhang

An unusual ten-connected self-penetrating metal–organic framework based on tetranuclear cobalt clusters

The unusual ten-connected self-penetrating metal-organic framework based on tetranuclear cobalt clusters has been synthesized and characterized, which represents the highest-connected uninodal network topology presently known for self-penetrating systems.

N-bromosuccinimide/1,8-diazabicyclo[5.4.1]undec-7-ene combination: β-amination of chalcones via a tandem bromoamination/debromination sequence.

A one-pot cascade transformation of chalcones into β-imidoketones has been developed, in which NBS provides both electrophilic bromine and nucleophilic nitrogen sources, and DBU functions as a nucleophilic reagent to activate NBS to be a more electrophilic bromine species and to further remove the bromine of α-bromoketones. The whole process involves tandem bromoamination and debromination, which represents a unique example of preparing β-aminoketones by the reaction of chalcones with the NBS/DBU combination.

Polarity-Reversible Conjugate Addition Tuned by Remote Electronic Effects

A new concept, polarity-reversible conjugate addition, has been described, based on the findings that the polarity of a classical Michael acceptor can be reversed through remote electronic effects. In addition, the remote electronic effects are tunable, and both five- and six-membered nitrogen rings can be constructed starting from acyclic precursors having the same enone structure unit simply by varying a remote substituent in the molecules.

Mechanistic understanding of domino cyclization between gem-dialkylthio vinylallenes and benzylamine towards economic synthesis: a computational study

DFT investigations are carried out to improve the domino cyclization between gem-dialkylthio vinylallenes and benzylamine. Economic reaction approaches were explored, namely, this reaction can occur under organic solvent-free conditions either catalyzed by trace water or self-catalyzed by BnNH2. Three types of reactions (DMSO-assisted, trace water-catalyzed, and self-catalyzed by BnNH2) shared the same reaction mechanism with the nucleophilic attack of BnNH2 on the allenic carbon of thioamide intermediate Re. For trace water-catalyzed reaction another mechanism was also found that is the BnNH2 attacks the carbonyl carbon of the conformational isomer of Re. Among the investigated mechanisms, the trace water-catalyzed one is suggested to be the most efficient and convenient synthetic method for pyrroles. Our calculated results were further confirmed by the experimental observation, which opens a new strategy for the synthesis of pyrroles.

Alkyne aminohalogenation enabled by DBU-activated N-haloimides: direct synthesis of halogenated enamines

Activated by DBU, N-haloimides can be used as both halogen and nitrogen sources to achieve the difunctionalization of terminal alkynes, giving rise to useful halogenated enamines with high efficiency and high regio- and stereoselectivities. The cascade reaction features simple manipulation, mild conditions, a broad substrate scope, readily available reagents, and atom-economy.

Organocatalyzed Anion Relay Leading to Functionalized 2,3-Dihydrofurans

A DABCO-mediated organocatalyzed anion relay cascade based on 1-cinnamoylcyclopropanecarboxamides has been developed and applied in the construction of 2,3-dihydrofurans with the original alkene and amide functionalities intact. In the aza-oxy-carbanion relay process, DABCO provides both the electron source and sink. The enolate anion-triggered ring opening of the cyclopropane is ascribed to the key step in the anion relay cascade.

Otherwise inert reaction of sulfonamides/carboxamides with formamides via proton transfer-enhanced reactivity

NBS-mediated addition-elimination reaction of sulfonamides/carboxamides and formamides afforded N-sulfonylamidines and N-formylarylamides, respectively, depending on the different mechanism of elimination. Hydrogen bond-induced proton transfer leads to enhanced reactivities and was proposed as the key driving force for the reaction to take place. The protocol demonstrates the possibility of constructing chemical bonds based on a proton transfer strategy induced by noncovalent hydrogen bond interaction.

Two unique 8-quinolinato (q) based one dimensional complexes [FeIIMnII(q)4·(H2O)0.25]n and [MnII(q)2]n: synthesis, structures, and magnetism

Herein, we report the first incorporation of 8-hydroxyquinoline ions into hetero- and homometallic one dimensional complexes [FeIIMnII(8-quinolinato)4·(H2O)0.25]n (1) and [MnII(8-quinolinato)2]n (2). Magnetic analyses of both complexes indicate antiferromagnetic interactions between the magnetic centers.