Methyl trifluoromethyl sulfone

The dipolarophile was prepared in a short (three-step) sequence from methyl phenyl sulfone (38% overall yield) and ethyl trifluoroacetate. Desulfonation, followed by reductive N-0 cleavage afforded the syn aminoalcohols [246]. Conjugate additions to the sulfone were described some years earlier [247] more recently, trifluoromethyl pyrroles have been synthesised from the nitro-propene [248]. 

E)-3-Arylidenethiochroman-4-oncs possess thioether and oi,[)-unsaturatcd ketone functionalities both of which are susceptible to oxidation by DMD. In fact, chemoselective oxidation at sulfur is observed with a separable mixture of the sulfoxide and sulfone being produced in >5 1 ratio. A similar situation holds for the related thioflavanones. Epoxidation of the alkenic double bond in the thiochromanone 1,1-dioxides alone can be achieved using methyl(trifluoromethyl)-dioxirane (Scheme 65) <1994T13113>. However, reaction of NaOCl with 3-arylidenethioflavanones gives the epoxide and subsequent oxidation with DMD then gives a mixture of the sulfoxide and sulfone <2003MRC193>. 

Organic fluorine compounds and methods for their preparation are the central topic of the next four procedures. Much of the synthetic versatility of methyl phenyl sulfone is embodied in FLUOROMETHYL PHENYL SULFONE and the fluoro Pummerer reaction of methyl phenyl sulfoxide with DAST is a key step in its preparation. The utility of this fluoromethyl sulfone in the preparation of fluoroalkenes Is demonstrated in a companion procedure for Z-[2-(FLUOROMETHYLENE) CYCLOHEXYL]BENZENE, a procedure with several prominent stereoselective features. Geminal difluoroalkenes are featured in the following procedure. (3,3 DIFLUOROALLYL)TRIMETHYLSILANE is prepared by a method in which the radical addition of dibromodifluoromethane to alkenes and the selective reduction of a-bromoalkylsilanes are key steps. A procedure for nucleophilic introduction of the trifluoromethyl group completes this set. The key reagent, (TRIFLUOROMETHYL)-TRIMETHYLSILANE is obtained by reductive coupling of TMS chloride and bromotrifluoromethane. Liberation of a CF3- equivalent with fluoride ion in the presence of cyclohexanone affords 1-TRIFLUOROMETHYL-1-CYCLOHEXANOL. 

T rifi uoro-2 -methyl-4 -(phenylsulfonyl) methanesulfonanilide 1,1,1-Trifluoro-N-[2-methyl-4-(phenylsulfonyl) phenyl] methanesulfonamide. See Perfluidone Trifluoromethyl sulfonic acid. See Trifluoromethane sulfonic acid (Trifluoromethyl) trifluorooxirane. See 1,2-Epoxy-1,1,2,3,3,3-hexafluoropropane (Trifluoromethyl) undecafluorocyclohexane 1-Trifluoromethyl-1,2,2,3,3,4,4,5,5,6,6-undecafluorocyclohexane. See Perfluoromethylcyclohexane Trifluoromonobromomethane. See Trifluorobromomethane Trifluoromonochlorocarbon. See Chlorotrifluoromethane Trifluoromonochloroethylene. See Chlorotrifluoroethylene... 

The similar alkoxide- or hydroxide-induced trifluoromethylation was also found to work with other electrophiles. Diphenyl disulfide can be trifluoromethylated to give trifluoromethyl phenyl sulfide in 87% yield (eq 4). Methyl benzoate can be trifluoromethylated to generate 2,2,2-trifluoroacetophenone in 30% yield at temperatures between —50°C and —20°C. Trifluo-romethylcopper (CF3CU) can be generated in situ with trifluoromethyl sulfone, f-BuOK, and copper iodide (Cul), and it then further reacts with iodobenzene at 80 °C for 20 h to give a,a,a-trifluorotoluene in 26% 3neld. ... 

The hydrophilic group numbers of the sodium sulfonate (SOj Na+) is +11.0, of methylene (CH2) groups (and also for the methyl group) -0.475, and of difluoromethylene (CF2) groups (also valid for the trifluoromethyl group)... 

Dimerization of sulfene yields disulfone 546, whose protons are readily replaced by deuterium, bromine, or trimethylsilyl groups. Sulfone 546 reacts with 2,6-dimethyl-4-pyrone to give an exo-methylene derivative and it may be tetra-methylated. Other disulfones are obtained by oxidation of 1,3-dithietanes with potassium permanganate or chromium trioxide-fuming nitric acid for resistant dithietanes. As mentioned above, peracetic acid oxidizes a disulfoxide, mono-sulfone, or a monosulfone-monosulfoxide to the disulfone 546. 57b,iii3a 2,2,4,4-Tetra(trifluoromethyl)-l,3-dithietane 537 is oxidized only to the monosulfone 547, even with chromium trioxide-hot, fuming nitric acid the disulfone is only... 

Without any experimental data available for comparison, Shao et al. also proposed and investigated sulfones with different functionalities as solvents [61]. By, e.g., replacing the ether functionality of MEMS with a carbonate, ester, or cyano terminated alkane chain, they in all cases predicted an approximate 0.5 eV increase in (MP2, TD cycle). Other substitutions produced similar effects a trifluoromethyl group for the terminal methyl group (MEMS or EMES), but if also a fluoro atom was introduced in place of the alkane group directly bonded to the sulphur, this second substitution introduced a further 0.5 eV or 1.0 eV stabilization of the solvents with an ester or cyano functionality, respectively. In addition to the TD cycle, adiabatic gas phase IP computations predicted EMS to be the most stable of the linear solvents and supported the stabilizing effects upon functionalization qualitatively [61],... 

The mechanism of activation of deoxyribonucleoside phosphoramidites by IH-tetrazole has recently attracted considerable attention. It has been argued that the protonation of the phosphoramidite function by l f-tet azole was rapid and followed by the reversible and slower formation of a phosphorotetrazolide intermediate (39). It is to be noted that relative to 5-(p-nitrophenyl)- IH-tetrazole (55), 1 -hydroxy-benzotriazole (24), / /-methylanilinium trifluoroacetate (40), iV-methyl-anilinium trichloroacetate (41), 5-trifluoromethyl-l//-tetrazole (23), A-methylimidazole hydrochloride (23), and )V-methylimidazole-trifluoromethane sulfonate (42), which have also been tested as activators, l/f-tetrazole still remained the most commonly used reagent for the activation of deoxyribonucleoside phosphoramidites. 

Prakash and co-workers have prepared monofluoro-methyl 3,5-bis(trifluoromethyl)phenyl sulfone and have used it in the fluoroalkenylation of aldehydes and ketones.They employ KOH or CsF as base in DMSO at 20°C. On their side, Hu and co-workers have developed TBTSO2CH2F as a versatile fluoromethylidene synthon. Difluoromethyl 2-pyridyl sulfone has been used for the gem-difluoromethylenation of aldehydes and ketones and was found to be a more efficient difluoromethyfidene synthon than BTSO2CF2H, PTSO2CF2H and TBTS02CF2H. ... 

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