Two-Step Synthesis of 2-Trifluoromethylated and 2-Difluoromethylated Benzoheteroles Starting from HFO-1224yd() and HFO-1233yd().

An efficient two-step method for synthesizing 2-(trifluoromethyl)- and 2-(difluoromethyl)benzoheteroles bearing various substituents was developed. Commercially available HFO-1224yd() or HFO-1233yd() underwent the Suzuki-Miyaura coupling with arylboronic acids (acid esters) bearing a nucleophilic moiety at the position to yield the corresponding β-fluoro-β-(trifluoromethyl)- or β-fluoro-β-(difluoromethyl)styrenes, respectively. Treatment of the obtained styrenes with potassium phosphate induced nucleophilic 5-- cyclization to provide the corresponding 2-trifluoromethylated or 2-difluoromethylated indoles and benzofurans, as well as benzothiophenes.

An -Fluorinated Imide for Practical Catalytic Imidations.

Catalytic imidation using NFSI as the nitrogen source has become an emerging tool for oxidative carbon-nitrogen bond formation. However, the less than ideal benzenesulfonimide moiety is incorporated into products, severely detracting its synthetic value. As a solution to this challenge, we report herein the development of a novel -fluorinated imide, -fluoro--(fluorosulfonyl)carbamate (NFC), by which the attached imide moiety acts as a modular synthetic handle for one-step derivatization to amines, sulfonamides, and sulfamides.

Highly Active Cross-Metathesis of Tetrafluoroethylene with a Seven-Membered N-Heterocyclic-Carbene-Ruthenium Catalyst.

A drastic increase in catalyst turnover number (TON) was accomplished in the cross-metathesis of tetrafluoroethylene (TFE) and vinyl ethers. Under a continuous flow of TFE, catalyst , which contains a seven-membered N-heterocyclic carbene (NHC) ligand, reached a TON of 4100; this is 2 orders of magnitude higher than the highest hitherto reported value. Mechanistic studies revealed that the expanded NHC successfully destabilizes the stable intermediates with a difluorocarbene structure, which strongly promotes the reaction.

Bench-Stable Electrophilic Fluorinating Reagents for Highly Selective Mono- and Difluorination of Silyl Enol Ethers.

Efficient methods for the synthesis of fluorinated compounds have been intensively studied, recently. Development of practical fluorinating reagents is indispensable for this purpose. Herein, bench-stable electrophilic fluorinating reagents were synthesized as N-fluorobenzenesulfonimide (NFSI) substitutes.

1-trifluoromethylvinylsilane as a CF2=C(-)-CH2+ synthon: synthesis of functionalized 1,1-difluoro-1-alkenes via isolable 2,2-difluorovinylsilanes.

Various 1,1-difluoro-1-alkenes such as monosubstituted 1,1-difluoro-1-alkenes, 2-bromo-1,1-difluoro-1-alkenes, and 3,3-difluoroallylic alcohols are synthesized in two simple steps from 1-trifluoromethylvinylsilane: (i) its SN2' reaction with nucleophiles to construct 2,2-difluorovinylsilanes and (ii) the subsequent substitution of electrophiles for the vinylic silyl group. The combination of these two processes allows a one-pot synthesis of the functionalized 1,1-difluoro-1-alkenes starting from 1-trifluoromethylvinylsilane, which functions as a CF2=C(-)-CH2+ synthon.