Publications by authors named "Hejun An"

Chiral phosphorus-containing compounds find applications across various fields, including asymmetric catalysis, medicinal chemistry, and materials science. Despite the abundance of reported highly enantioselective methods for synthesizing various chiral phosphorus compounds, the enantioselective synthesis of α-boryl phosphorus compounds still remains an unknown territory. Here, we report a method for the construction of chiral α-boryl phosphates by asymmetric B-H insertion reaction using α-diazo phosphates as carbene precursors, cheap and readily available copper salt as the catalyst and chiral oxazoline as the ligand.

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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.

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A novel radical-involved alkene difunctionalization catalyzed by the copper/Bpin system has been developed, leading to the difluoroalkylation-thiolation of aryl alkenes. The use of Bpin as an organic reductant enables the simultaneous installation of a C(sp)-C(FR) bond and a C(sp)-S(R) bond across the C═C bond of aryl alkenes by utilizing two electrophilic reactants. The reaction exhibits broad substrate scope, excellent diastereoselectivity, and moderate to good yields.

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Photoredox-catalyzed decarboxylative alkylation of silyl enol ethers has been developed. Diverse functionalized aryl alkyl ketones were afforded in modest to good yields using N-(acyloxy)phthalimide as an easy access alkyl radical source under mild and operationally simple conditions. The excellent performance of drug molecules such as fenbufen and indomethacin and naturally occurring carboxylic acids such as stearic acid and dehydrocholic acid further demonstrated the practicability of the reaction.

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An unconventional reductive quenching cycle was developed to realize the visible-light-induced thiotrifluoromethylation of terminal alkenes. CFSONa was used as an easy to handle CF radical source to afford the desired products in moderate to good yields. Mild reaction conditions and a broad substrate scope feature in this transformation.

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