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Although the development of radical chain and photocatalytic borylation reactions using N‐heterocyclic carbene (NHC)‐borane as boron source is remarkable, the persistent problems, including the use of hazardous and high‐energy radical initiators or the recyclability and photostability issues of soluble homogeneous photocatalysts, still leave great room for further development in a sustainable manner. Herein, we report a conceptually different approach toward highly functionalized organoborane synthesis by using recoverable ultrathin cadmium sulfide (CdS) nanosheets as a heterogeneous photocatalyst, and a general and mild borylation platform that enables regioselective borylation of a wide variety of alkenes (arylethenes, trifluoromethylalkenes, α,β‐unsaturated carbonyl compounds and nitriles), alkynes, imines and electron‐poor aromatic rings with NHC‐borane as boryl radical precursor. Mechanistic studies and density functional theory (DFT) calculations reveal that both photogenerated electrons and holes on the CdS fully perform their own roles, thereby resulting in enhancement of photocatalytic activity and stability of CdS. [ABSTRACT FROM AUTHOR]

A pyridinium salt catalyzed radical borylation of benzoyl peroxides is reported herein. A range of benzoyl peroxides having different electronic properties were well compatible in this borylation reaction, delivering various arylboronates in good yields at ambient temperature. The current method features simple operation, additive- and base-free, transition-metal-free and mild conditions.

A one-pot two-step protocol for the direct synthesis of boron-handled glycol derivatives is reported. The procedure starts by an NHC–boryl-radical-promoted regioselective hydroboration of glycol-protected cinnamaldehydes. After that, the reaction mixture is treated with pinacol in the presence of HCl, leading to the direct formation of pinacol boronate handled glycol monoalkyl ethers. In this acid-triggered conversion, a reductive ring-opening of glycol-derived acetal moiety takes place, during which an NHC–borane unit serves as the hydride source. [ABSTRACT FROM AUTHOR]

In this Communication, we report an unprecedented β‐regioselective radical inverse hydroboration (compared with ionic hydroboration) of α,β‐unsaturated amides with NHC‐BH3 enabled by photoredox catalysis. Density functional theory (DFT) calculations show that the unique photoredox cycle is a key factor to control the β‐regioselective radical hydroboration, by lowering the energy barrier in comparison with other pathways. This protocol provides a general and convenient route to construct a wide range of structurally diverse β‐borylated amides in synthetically useful yields under mild conditions. [ABSTRACT FROM AUTHOR]

In this Communication, we report an unprecedented b-regioselective radical inverse hydroboration (compared with ionic hydroboration) of α,β-unsaturated amides with NHCBH3 enabled by photoredox catalysis. Density functional theory (DFT) calculations show that the unique photoredox cycle is a key factor to control the β-regioselective radical hydroboration, by lowering the energy barrier in comparison with other pathways. This protocol provides a general and convenient route to construct a wide range of structurally diverse b-borylated amides in synthetically useful yields under mild conditions. [ABSTRACT FROM AUTHOR]

Herein, we report a radical borylation of aromatic amines through a homolytic C(sp2)−N bond cleavage. This method capitalizes on a simple and mild activation via a pyrylium reagent (ScPyry‐OTf) thus priming the amino group for reactivity. The combination of terpyridine and a diboron reagent triggers a radical reaction which cleaves the C(sp2)−N bond and forges a new C(sp2)−B bond. The unique non‐planar structure of the pyridinium intermediate, provides the necessary driving force for the aryl radical formation. The method permits borylation of a wide variety of aromatic amines indistinctively of the electronic environment. [ABSTRACT FROM AUTHOR]