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A strategy of chemoselective reduction of α, β-unsaturated ketones was developed in our group. H3N·BH3 would prefer to coordinate with CO bond, forming six-membered ring, and ketones were hydrogenated via concerted double-hydrogen-transfer process.

Inspired by the body circulation of Omeprazole (irreversible proton pump inhibitor), we disclose the carbene-triggered cascades for the synthesis of 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing thiocarbamates, which represents an unprecedented imine derivative migration process. Furthermore, the desulfurizing reagent-free Barton-Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles have also been achieved for the first time, and elemental sulfur is confirmed as a byproduct during this transformation. Both experimental data and DFT calculations further thoroughly explained the unique reactivity.

In the presence of K2S2O8 and HOAc, 3-(2-azidoaryl) substituted propargyl alcohols can go through chemoselective oxidative radical cyclizations to give a pool of anthranils based on Meyer-Schuster rearrangement. It's proposed that the cyclizations were triggered exclusively by the direct attack of oxygen radicals on the azides. The weak N-O bonds in anthranils could be easily cleaved in the presence of transition metal catalysts and went through aminations with 2-oxo-2-phenylacetic acid and iodobenzene.

An expedient strategy for the synthesis of 5-oxazole ketones was developed via homogeneous gold catalysis with 4-MeO-TEMPO as an oxidant. The desired 5-oxazole ketones were achieved in decent yields with an excellent functional group compatibility under mild conditions. The current protocol also represents the first example for merging a gold catalyst and radical chemistry in one-pot synthesis with internal N-propargylamides.

An expedient strategy of reductive N-alkylation of amines with readily available carboxylic acids as alkylating reagents has been developed. Commercially available and hydrogen rich ammonia borane (H3B·NH3) was employed as a practical hydrogen source. Mono- and dialkylated products of primary amines could be selectively obtained by varying the reaction conditions. Complementary to known reductive aminations, this strategy showed excellent functional group compatibility, and a broad range of secondary and tertiary amines, including drug molecules, were obtained smoothly.

A novel copper(I)-catalyzed chemoselective reduction of the carbonyls of benzofuran-2-yl ketones over furan rings with B2pin2 has been developed. This reaction proceeded under mild conditions. High valuable secondary alcohol derivatives of benzofurans were obtained in good to excellent yields with a broad substrate scope. The mechanistic studies suggested that a domino-borylation-protodeboronation pathway was involved in this reaction.

H2O is routinely described as a proton donor, however, in the presence of diboron compounds, the umpolung reaction of H2O under metal-free conditions was successfully developed, which could afford hydride species, leading to a highly efficient and chemoselective reduction of CO bonds. This strategy exhibits excellent chemoselectivities toward carbonyl groups in the presence of ester, olefin, halogen, thioether, sulfonyl, cyano as well as heteroaromatic groups.

An efficient, convenient and mild Ru-catalyzed reductive amination reaction was developed by employing H2O as both hydrogen source and solvent via B2(OH)4/H2O systems. The reaction proceeded smoothly under air at ambient temperature and exhibited excellent chemoselectivities toward unsaturated and heteroaromatic as well as aliphatic aldehydes. Interestingly, α-deuterated amines were also obtained expediently by employing D2O in our catalytic systems.

An expedient and stereoselective synthesis of functionalized trisubstituted allylic boronates via direct borylation of Morita–Baylis–Hillman alcohols is disclosed. The reaction proceeds smoothly at ambient temperature with high atomic and synthetic efficiency. The desired allylic boronates can be applied in the efficient synthesis of homoallyl alcohols and α-exomethylene γ-lactones.

A novel copper(I)-catalyzed chemoselective reduction of the carbonyls of benzofuran-2-yl ketones over furan rings with B

H

A Pd-catalyzed transfer hydrogenation of various N-heteroaromatic compounds with B2pin2 as a mediator and environmentally benign water as both solvent and hydrogen donor has been disclosed. This reaction proceeded under ambient temperature with a broad range of N-heteroaromatic compounds among which imidazo[1,2-a]pyridine derivatives were for the first time selectively reduced to 5,6,7,8-tetrahydroimidazo[1,2-a]pyridines, which are the core structural motifs of an inhibitor of human O-GlcNAcase. Mechanistic studies suggested that the new protons in products are from water and Pd–H might be the key intermediate with B2pin2 as the H2O activator.