Hu Cai

Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions

Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.

A simple protocol for Cu-catalyzed protodecarboxylation of (hetero)aromatic carboxylic acids

A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials.

Metal-free phosphonation of benzoxazoles and benzothiazoles under oxidative conditions

An iodine promoted phosphonation of benzoxazoles and benzothiazoles with trialkyl phosphites was described. This reaction undergoes three steps: an addition procedure, followed by a radical oxidation, and an elimination reaction, provides an efficient method to access 2-phosphated products with a broad scope of substrates.

Mono- and bis-N-heterocyclic carbene complexes of tantalum and niobium with high oxidation states

Reactions of two free N-heterocyclic carbenes (NHCs) 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-dimesitylimidazol-2-yliden (IMes) with group VB transition metals MCl5 at low temperature gave a mono-NHC complex [(IPr)TaCl5] (1) and two bis-NHCs [(IMes)2MCl4][MCl6] (M = Ta, 2; =Nb, 3). Crystallographic studies revealed that the substitution effect plays an important role in the construction of these two different types of NHC complexes. Although mono-NHC complex 1 has been theoretically analyzed by F. Marchetti, complexes 2 and 3 represented the first examples of the structurally characterized bis-NHCs Ta(V) and Nb(V) complexes. In addition, complexes 1–3 showed catalytic efficiency in the cycloaddition between CO2 and propylene oxide to synthesize cyclic carbonates under mild conditions.

Selective Phosphoramidation and Phosphonation of Benzoxazoles via Sequence Control

A selective phosphoramidation and phosphonation of benzoxazole was developed with trialkyl phosphites in the presence of iodine under mild conditions. In the reaction, the transformation completes in 10 min at room temperature and the substrates are well tolerant, as 2-substituted azoles could afford the quaternary carbon-centered products. Significantly, phosphites could be selectively introduced into the C- and N-positions of the benzoxazoles by controlling the addition sequence and the ratio of substrates.

Reversible solid-state thermochromism of a 2D organic–inorganic hybrid perovskite structure based on iodoplumbate and 2-aminomethyl-pyridine

An organic–inorganic hybrid molecule [(PyCH2NH3)6][Pb5I22]·3H2O (1) with a 2D inorganic layer was produced by reaction of 2-aminomethyl-pyridine with PbI2 in a concentrated HI aqueous solution. Compound 1 exhibited solid thermochromism showing a reversible color change from orange at room temperature to red at 80 °C, which was caused by the structural changes.

Synthesis of (pentafluorophenyl)benzenes via Pd-catalyzed C–H arylation of pentafluorobenzene with aryliodine diacetates

A streamlined Pd-catalyzed direct oxidative arylation of the pentafluorobenzene C–H bond with readily available (diacetoxyiodo)arenes has been described. Under the optimized conditions, three (diacetoxyiodo)arene derivatives were found to undergo coupling with pentafluorobenzene to furnish the substituted (pentafluorophenyl)benzenes in moderate to good yields.

Convenient sulfonylation of imidazoles and triazoles using NFSI

ABSTRACT A protocol for the synthesis of N-sulfonyl imidazoles and triazoles has been achieved using N-Fluorobenzenesulfonimide as a sulfonyl source. This reaction proceeded well in the absence of strong bases and catalysts, providing a convenient alternative method for the preparation of N-sulfonyl imidazoles as well as triazoles. GRAPHICAL ABSTRACT

Copper‐Catalyzed C‐2 and C‐3 Phosphonation of Benzofuran and Benzothiophene with Trialkyl Phosphite

A strategy for the selective phosphonation of benzofuran and benzothiophene with trialkyl phosphites was developed. In these reactions, the C−H phosphonation of benzofurans or benzothiophenes at the C2 or C3 position with trialkyl phosphites was successfully achieved without directing groups by using a copper catalyst. Additionally, the C5 phosphonation of furan was successful under the same conditions.