Junji Ichikawa

A novel synthesis of 1,1-difluoroolefins from 1,1,1-trifluoroethyl p-toluenesulfonate VIA boron ate-complex

Abstract The nucleophilic substitution of gem -difluorovinylic tosyloxy group with alkyl groups is effected by treating 2,2-difluoro-1-tosyloxyvinyllithium with trialkylboranes to afford 1,1-difluoroolefins in good yields.

A one-pot synthesis of 2,2-difluorovinyl carbonyl compounds from 2,2,2-trifluoroethyl p-toluenesulfonate via 2,2-difluorovinylboranes

Abstract 2,2,2-Trifluoroethyl p-toluenesulfonate is treated with butyllithium and trialkylboranes successively to generate 1-alkyl-2,2-difluorovinylboranes, which in turn react with acyl chlorides or chloroformates in the presence of cuprous iodide to afford 2,2-difluorovinyl carbonyl compounds in good yields.

Reactions of 2,2-difluoroalkenylboranes with halogens in the presence of base. Novel syntheses of symmetrically disubstituted 1,1-difluoro-1-alkenes and 1,1-difluoro-2-iodo-1-alkenes

Abstract Treatment of 2,2-difluoroalkenylboranes with bromine and iodine causes coupling reaction and halogenolysis to afford the title compounds in a reverse manner to nonfluorinated counterpart.

Syntheses and lipophilicities of tetraarylborate ions substituted with many trifluoromethyl groups

Abstract Syntheses were investigated using various tetraarylborate ions with a large number of trifluoromethyl groups: tetrakis[3,5-bis(trifluoromethyl)phenyl]borate; tetrakis [3,5-bis(1-methoxy-2,2,2-trifluoro-1-(trifluoromethyl)ethyl) phenyl] borate; tetrakis[3-(1- methoxy-2,2,2-trifluoro-1-(trifluoromethyl)ethyl)-5-(trifluoromethyl)phenyl] borate; and tetrakis[3-(2,2,2- trifluoro-1-(2,2,2-trifluoroethyoxy)-1-(trifluoromethyl)ethyl)-5- (trifluoromethyl)phenyl]borate ions. The preparation of Grignard reagents and the subsequent reaction with boron trifluoride etherate are important steps for a higher yield and easier isolation of the product. Sodium- and tetramethylammonium salts of these borate ions are soluble in halocarbon solvents such as dichloromethane, chloroform and 1,2-dibromotetrafluoroethane.

A novel synthesis of difluoromethyl ketones from 2,2,2-trifluoroethyl p-toluenesulfonate via 2,2-difluoroalkenylboranes

Abstract Oxidation of 2,2-difluoroalkenylboranes can be achieved with alkaline hydrogen peroxide in the presence of sodium methoxide, which suppresses protonolysis, to afford difluoromethyl ketones in good yields.

Syntheses of lipophilic tetraarylborate ions substituted with many perfluoroalkyl groups and their stability under acid conditions

Abstract Syntheses are investigated on several new kinds of perfluoroalkyl-substituted tetraarylborate ions such as tetrakis(3,5-bis(nonafluorobutyl)phenyl)borate, tetrakis(3,5-bis(heptafluoro-2-propyl)phenyl)borate ( PFPB ), tetrakis(3-(heptafluoro-2-propyl)-1-(trifluoromethyl)phenyl)borate, and tetrakis(3-(heptafluoro-2-propyl)phenyl)borate. Solubilities of tetramethylammonium tetraarylborates in some hydrophobic halocarbon solvents and rate constants of acid-catalyzed decomposition of the tetraarylborate ions in methanolic sulfuric acid solutions and in dichloromethane/aqueous sulfuric acid two-phase system are determined. Trifluoromethyl- and perfluoroalkyl-substituent effects on the lipophilicity and chemical stability of the tetraarylborate ions are discussed in comparisons with a range of those described previously.