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The reaction regioselectivity of gem‐difluoroalkenes is dependent on the intrinsic polarity. Thus, the reversal of the regioselectivity of the addition reaction of gem‐difluoroalkenes remains a formidable challenge. Herein, we described an unprecedented reversal of regioselectivity of hydrogen atom transfer (HAT) to gem‐difluoroalkenes triggered by Fe−H species for the formation of difluoroalkyl radicals. Hydrogenation of the in situ generated radicals gave difluoromethylated products. Mechanism experiments and theoretical studies revealed that the kinetic effect of the irreversible HAT process resulted in the reversal of the regioselectivity of this scenario, leading to the formation of a less stable α‐difluoroalkyl radical regioisomer. On basis of this new reaction of gem‐difluoroalkene, the iron‐promoted hydrohalogenation of gem‐difluoroalkenes for the efficient synthesis of aliphatic chlorodifluoromethyl‐, bromodifluoromethyl‐ and iododifluoromethyl‐containing compounds was developed. Particularly, this novel hydrohalogenation of gem‐difluoroalkenes provided an effect and large‐scale access to various iododifluoromethylated compounds of high value for synthetic application. [ABSTRACT FROM AUTHOR]

The present study reports an unprecedented protocol for the phosphonylation of unactivated C(sp3)−H bonds. By utilizing 1 mol % 4DPAIPN (1,2,3,5‐tetrakis(diphenylamino)‐4,6‐dicyanobenzene) as the catalyst, satisfactory yields of γ‐phosphonylated amides are obtained through a visible‐light‐induced reaction between N‐((4‐cyanobenzoyl)oxy)alkanamides and 9‐fluorenyl o‐phenylene phosphite at room temperature. This protocol demonstrates broad substrate scope and wide functional group compatibility. [ABSTRACT FROM AUTHOR]

The development of aryl alkyl sulfides as dichotomous electrophiles for site‐selective silylation via C−S bond cleavage has been achieved. Iron‐catalyzed selective cleavage of C(aryl)−S bonds can occur in the presence of β‐diketimine ligands, and the cleavage of C(alkyl)−S bonds can be achieved by t‐BuONa without the use of transition metals, resulting in the corresponding silylated products in moderate to excellent yields. Mechanistic studies suggest that Fe−Si species may undergo metathesis reactions during the cleavage of C(aryl)−S bonds, while silyl radicals are involved during the cleavage of C(alkyl)−S bonds. [ABSTRACT FROM AUTHOR]

The transition metal‐catalyzed cross‐coupling reaction with Fischer metal carbene intermediates bearing an electron‐rich alkoxyl or siloxyl group remains a big challenge due to the lack of readily available corresponding carbene precursors. Herein, we report the coupling of alkynes with the Fischer‐type copper carbene species bearing a α‐siloxyl group, which could be in situ generated from acylsilanes catalytically under photoirradiation and redox‐neutral conditions. The side‐arm modified bisoxazoline (SaBox) ligands prove to be crucial for this coupling reaction, which provides the corresponding alkynyl alcohol in high yields with remarkable heterocycle tolerance and broad substrate scope. [ABSTRACT FROM AUTHOR]

Atroposelective electrophilic sulfenylation of N‐aryl aminoquinone derivatives has been achieved for the first time. This transformation is enabled by a new chiral 6,6′‐disubstituted SPINOL‐derived sulfide catalyst, which was first synthesized and then successfully explored for catalyzing enantioselective reactions. Various axially chiral sulfur‐containing diarylamine derivatives were readily obtained in moderate to excellent yields with moderate to excellent enantioselectivities. A class of relatively flexible stereogenic C−N axes was easily constructed. The experimental results and a computational study suggested that an intramolecular N−H⋅⋅⋅S hydrogen bond is important for the stability of the C−N axis, which is consistent with our hypothesis. Density functional theory calculations revealed the origin of atroposelectivity and underscored the importance of catalyst rigidity in this sulfenylation reaction. [ABSTRACT FROM AUTHOR]

An asymmetric 1,6-conjugate addition of thioacetic acid with para-quinone methides has been developed by using chiral phosphoric acid catalysis in the presence of water. A series of sulfur-containing compounds were thus obtained in high yields with good to excellent enantioselectivities. Theoretical studies indicated that the water-bridged proton transfer is a potentially favorable reaction pathway. An unprecedented O−H⋅⋅⋅π interaction between water and the aromatic nucleus of chiral phosphoric acid was discovered to contribute significantly to the stereocontrol in the catalysis. [ABSTRACT FROM AUTHOR]