Substituent Effects on the Solvolysis of 1,1-Diphenyl-2,2,2-trifluoroethyl Tosylates: Comparison between Symmetrically Disubstituted and Monosubstituted Systems
The solvolysis rates of 1-(substituted phenyl)-1-phenyl-2,2,2-trifluoroethyl and 1,1-bis(substituted phenyl)-2,2,2-trifluoroethyl tosylates or bromides were conductimetrically measured at 25.0 °C i...
A micro‐flow nucleophilic trifluoromethylation of carbonyl compounds using gaseous fluoroform was developed. This method also allows the first micro‐flow transformation of N‐sulfinylimines into trifluoromethyl amines with excellent diastereoselectivity. To demonstrate the synthetic utility of this micro‐flow synthesis, the formal micro‐flow synthesis of Efavirenz is described.
Solvolytic studies of the highly crowded 1-aryl-1-phenyl-1-(trifluoromethyl)methyl bromide and tosylates
作者:Kwang-Ting Liu、Mann-Yan Kuo
DOI:10.1016/s0040-4039(01)80816-9
日期:——
In the titled system the remarkably high tosylate/bromide solvolysis rate ratio of 1.56 × 106 : 1 indicates a highly strained ground state, and the reverse order of reactivity for substrate having 1-(4-trifluoromethyl)phenyl vs. that having 1-(3-trifluoromethyl)phenyl suggests the twisting of the aryl group from coplanarity in the cationic transition state.
The trifluoromethylation of carbonyl compounds is accomplished by the stable (trifluoromethyOzinc reagent generated and then isolated from CF3I and ZnEt2, which can be utilized as a trifluoromethyl anion source (CF3-). The reaction proceeds smoothly with diamine as a ligand and ammonium salt as an initiator, providing the corresponding trifluoromethylated alcohol products. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source (:CF2) not only for gem-difluoroolefination of carbonyl compounds with phosphine but also for gem-difluorocyclization of alkenes or alkynes via the thermal decomposition, respectively.