Exploration of the Synthetic Potential of Electrophilic Trifluoromethylthiolating and Difluoromethylthiolating Reagents.

Exploration of the Synthetic Potential of Electrophilic Trifluoromethylthiolating and Difluoromethylthiolating Reagents.
Angew Chem Int Ed Engl. 2018 Jul 10;:
Authors: Xue XS, Zhang J, Yang JD, Zheng H, Mayr H, Cheng JP
Abstract
Electrophilicity parameters (E) of some popular trifluoromethylthiolating and difluoromethylthiolating reagents were determined by following the kinetics of their reactions with a series of enamines and carbanions with known nucleophilicity parameters (N, sN), using the linear free-energy relationship log k2 = sN(N + E). The electrophilic reactivities of these reagents cover a range of 17 orders of magnitude, with Shen and Lu's reagent 1a being the most reactive and Billard's reagent 1h the least reactive electrophile. While the observed electrophilic reactivities (E) of the amido-derived trifluoromethylthiolating reagents correlate well with the calculated Gibbs energies of the heterolytic cleavage of the X-SCF3 bonds (Tt+DA), the cumol-derived reagents 1f and 1g are more reactive than expected from the thermodynamics of the O-S cleavage. The E parameters of tri(di)fluoromethylthiolating reagents derived in this work provide an ordering principle for their use in synthesis.
PMID: 29989309 [PubMed - as supplied by publisher]

Source: Angewandte Chemie - July 10, 2018 Category: Chemistry Authors: Xue XS, Zhang J, Yang JD, Zheng H, Mayr H, Cheng JP Tags: Angew Chem Int Ed Engl Source Type: research