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A nontrigonal phosphorus triamide ( 1 , P{N[ o -NMe-C 6 H 4 ] 2 }) is shown to catalyze C–H borylation of electron-rich heteroarenes with pinacolborane (HBpin) in the presence of a mild chloroalkane reagent. C–H borylation proceeds for a range of electron-rich heterocycles including pyrroles, indoles, and thiophenes of varied substitution. Mechanistic studies implicate an initial P–N cooperative activation of HBpin by 1 to give P -hydrido diazaphospholene 2 , which is diverted by Atherton–Todd oxidation with chloroalkane to generate P -chloro diazaphospholene 3 . DFT calculations suggest subsequent oxidation of pinacolborane by 3 generates chloropinacolborane (ClBpin) as a transient electrophilic borylating species, consistent with observed substituent effects and regiochemical outcomes. These results illustrate the targeted diversion of established reaction pathways in organophosphorus catalysis to enable a new mode of main group-catalyzed C–H borylation. 

The synthesis and catalytic reactivity of a class of water-tolerant cationic phosphorus-based Lewis acids is reported. Corrole-based phosphorus( v ) cations of the type [ArP(cor)][B(C 6 F 5 ) 4 ] (Ar = C 6 H 5 , 3,5-(CF 3 ) 2 C 6 H 3 ; cor = 5,10,15-(C 6 H 5 ) 3 corrolato 3− , 5,10,15-(C 6 F 5 ) 3 corrolato 3− ) were synthesized and characterized by NMR and X-ray diffraction. The visible electronic absorption spectra of these cationic phosphacorroles depend strongly on the coordination environment at phosphorus, and their Lewis acidities are quantified by spectrophotometric titrations. DFT analyses establish that the character of the P-acceptor orbital comprises P–N antibonding interactions in the basal plane of the phosphacorrole. Consequently, the cationic phosphacorroles display unprecedented stability to water and alcohols while remaining highly active and robust Lewis acid catalysts for carbonyl hydrosilylation, C sp3 –H bond functionalization, and carbohydrate deoxygenation reactions. 

We report here a “nonspectator” behavior for an unsupportedL‐function σ³‐P ligand (i.e. P{N[o‐NMe‐C₆H₄]₂},1a) in complex with the cyclopentadienyliron dicarbonyl cation (Fp⁺). Treatment of1a⋅Fp⁺with [(Me₂N)₃S][Me₃SiF₂] results in fluoride addition to theP‐center, giving the isolable crystalline fluorometallophosphorane1a^F⋅Fp that allows a crystallographic assessment of the variance in the Fe−P bond as a function of P‐coordination number. The nonspectator reactivity of1a⋅Fp⁺is rationalized on the basis of electronic structure arguments and by comparison to trigonal analogue (Me₂N)₃P⋅Fp⁺(i.e.1b⋅Fp⁺), which is inert to fluoride addition. These observations establish a nonspectator L/X‐switching in (σ³‐P)–M complexes by reversible access to higher‐coordinate phosphorus ligand fragments.

 

We report here a “nonspectator” behavior for an unsupportedL‐function σ³‐P ligand (i.e. P{N[o‐NMe‐C₆H₄]₂},1a) in complex with the cyclopentadienyliron dicarbonyl cation (Fp⁺). Treatment of1a⋅Fp⁺with [(Me₂N)₃S][Me₃SiF₂] results in fluoride addition to theP‐center, giving the isolable crystalline fluorometallophosphorane1a^F⋅Fp that allows a crystallographic assessment of the variance in the Fe−P bond as a function of P‐coordination number. The nonspectator reactivity of1a⋅Fp⁺is rationalized on the basis of electronic structure arguments and by comparison to trigonal analogue (Me₂N)₃P⋅Fp⁺(i.e.1b⋅Fp⁺), which is inert to fluoride addition. These observations establish a nonspectator L/X‐switching in (σ³‐P)–M complexes by reversible access to higher‐coordinate phosphorus ligand fragments.

 

The syntheses and 1,2-addition reactivities of nontrigonal phosphazenes supported by trianionic tricoordinating chelates of the type L₃PNdipp (3: L₃= N[CHC(^tBu)O]₂³⁻;4: L₃= N(o-NMeC₆H₄)₂³⁻; dipp = 2,6-diisopropylphenyl) are reported.