Concluding Remarks

Shaik, Sason; Stuyver, T.

doi:10.1039/9781839163043-00420

Cited by 1 publication

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This increasing order is the same as the decreasing order of the DEF A value. A similar role of local electrostatic field on reactivity has been recognized recently in enzymatic reactions, − organic reactions, − and reactions by transition metal complexes . The discussion presented here is essentially the same as those explanations; we presented the discussion on the comparison between TS 4/5 Aa and TS 4/5 C in page S19 of the Supporting Information because the comparison is a bit complex and distant from the main discussion.…”

Section: Resultsmentioning

confidence: 51%

Theoretical Study on Bismuth(III) Catalysts for Synthesis of Phenylsulfonyl Fluoride: Reasons of Their Catalysis

Tian,

Sakaki

2024

ACS Catal.

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Bismuth(III) complex with diarylsulfone ligand (diAr-SO 2 ) is a non-transition metal catalyst reported recently for the synthesis of arylsulfonyl fluorides. We investigated this catalytic reaction using DFT and SCS-MP2 calculations for geometries and energies, respectively. This catalytic reaction occurs through transmetalation between (BF 4 )Bi(diAr-SO 2 ) and phenylboronic acid (PhB(OH) 2 ), SO 2 insertion into the Bi−Ph bond of (Ph)Bi(diAr-SO 2 ), and fluorination of the PhOSO group of (PhOSO)Bi(diAr-SO 2 ) by Selectfluor. The rate-determining step is the transmetalation for diAr-SO 2 with (CH 3 , CH 3 ) and (CF 3 , CF 3 ) but either the transmetalation or fluorination for diAr-SO 2 with (CH 3 , CF 3 ), where (R 1 , R 2 ) means diAr-SO 2 has R 1 and R 2 substituents on its aryl groups. The activation energy (ΔG° ‡) of the rate-determining step increases in the order (CH 3 , CF 3 ) < (CH 3 , CH 3 ) < (CF 3 , CF 3 ). This increasing order is consistent with the experimentally observed substituent effects on catalytic activity. The transmetalation is difficult to occur in the absence of potassium phosphate (K 3 PO 4 ) but occurs with moderate activation energy in the presence of K 3 PO 4 because K 3 PO 4 activates the B−Ph σ-bond of phenylboronic acid and stabilizes the dissociating B(OH) 2 moiety through electrostatic interaction. The substituents on diAr-SO 2 play an important role in the transmetalation; when diAr-SO 2 has (CF 3 , CF 3 ), K 3 PO 4 strongly interacts with the Bi(diAr-SO 2 ) species to form an overly stable adduct to enlarge considerably the ΔG° ‡ value. When diAr-SO 2 has either (CH 3 , CF 3 ) or (CH 3 , CH 3 ), the stabilization energy of the adduct is similar to each other, but the energy destabilization occurs more largely upon going to the asymmetric transition state from the adduct in the (CH 3 , CH 3 ) case than in the (CH 3 , CF 3 ) case. Thus, the use of diAr-SO 2 with (CH 3 , CF 3 ) is favorable for the transmetalation. The SO 2 insertion into the Bi−Ph bond of (Ph)Bi(diAr-SO 2 ) occurs with a moderate ΔG° ‡ value, whereas the SO 2 insertion is difficult to occur when the sulfone (SO 2 ) group of diAr-SO 2 is replaced with a CH 2 group. The SO 2 insertion occurs via a nucleophilic attack of the Ph group to SO 2 . However, (Ph)Bi(diAr-SO 2 ) with (CH 3 , CH 3 ) is not the most reactive because not only the HOMO energy of (Ph)Bi(diAr-SO 2 ) but also factors such as the Bi δ+ − (C 6 H 3 R) δ− (R = CH 3 or CF 3 ) bond dipole moment and the Bi−C 6 H 3 R bond strength participate in determining the reactivity of (Ph)Bi(diAr-SO 2 ) for the SO 2 insertion where C 6 H 3 R is the aryl part of diArSO 2 . The fluorination occurs with a moderate ΔG° ‡ value and an extremely negative ΔG°value. Its ΔG° ‡ value hardly depends on the substituents of diAr-SO 2 . The presence of K 3 PO 4 and the use of diAr-SO 2 ligand with (CH 3 , CF 3 ) are key for the catalytic activity of the bismuth catalyst.

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