Partially fluorinated heterocyclic compounds. Part II. The preparation of 4,5,6,7-tetrafluorobenzo[b]thiophen by a new cyclisation reaction

Brooke, Gerald M.; Quasem, Md. Abul

doi:10.1039/j39670000865

Cited by 22 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hydrogen atom in pentafluorobenzene is so acidic that it reacts with organolithium compounds in a metathetical reaction and gives pentafluorophenyllithium [470,471]. This reaction is an alternative route to fluorinated organolithium compounds, which will be dealt with in the next paragraph.…”

Section: Organolithium Compoundsmentioning

confidence: 99%

Organic Fluorine Chemistry

Hudlický

1971

View full text Add to dashboard Cite

Section: Organolithium Compoundsmentioning

confidence: 99%

Organic Fluorine Chemistry

Hudlický

1971

View full text Add to dashboard Cite

“…The reaction with sulfur to give thiol 2 proceeds smoothly just as for C 6 F 5 Li with sulfur . In the reaction with selenium the selenophenol CF 3 C 6 F 4 OC 6 F 4 SeH that must be formed initially is not isolable; instead, it oxidizes to form the stable yellow diselenide 3 .…”

Section: Resultsmentioning

confidence: 94%

Synthesis and Chemistry of CF₃C₆F₄OC₆F₄ Group 14/16 Derivatives

1997

View full text Add to dashboard Cite

Reactions of 4‘-CF3C6F4OC6F4Li, generated in situ, with elements of group 16 (S, Se, Te) lead to CF3C6F4OC6F4SH (2), (CF3C6F4OC6F4Se)2 (3), and (CF3C6F4OC6F3Te)2 (4)/(CF3C6F4OC6F3)2Te (4a). The phenol derivative CF3C6F4OC6F4OH (1) is obtained by reaction of CF3C6F4OC6F4Li with B(OMe)3/H2O2. The reaction of CF3C6F4OC6F4Li with trimethylsilyl chloride or trimethyltin chloride gives CF3C6F4OC6F4XMe3 (X = Si (5), Sn (6)). Oxidation of 2 in the presence of bromine results in the formation of (CF3C6F4OC6F4S)2 (7) and CF3C6F4OC6F4SO2Br (8). Mixed perfluoroaryloxo/thio ethers CF3C6F4OC6F4SC6F4R (R = NO2 (9), CN (10), CF3 (11)) and CF3C6F4OC6F4SC5F4N (12) are obtained upon reaction of 2 with excess C6F5R and pentafluoropyridine in the presence of K2CO3. With 4-C6F5OC6F4NO2, a mixture of (2-CF3C6F4OC6F4S)(4-C6F5O)C6F3NO2 (13) and 9 is formed. Reaction of excess 2 with C6F5R gives the 2,4,6-substituted benzenes (CF3C6F4OC6F4S)3C6F2R (R = NO2 (14), CN (15)). The trimethylsilyl ether CF3C6F4OC6F4OSiMe3 (16) is prepared from the reaction of 1 with hexamethyldisilazane. 16 is a convenient reagent for the preparation of the aryl ethers CF3C6F4OC6F4OC6F4R (R = NO2 (17), CN (18)) and CF3C6F4OC6F4OC5F4N (19) upon reaction with C6F5R and C5F5N. The secondary alcohols CF3C6F4OC6F4CH(C6H5)OH (20) and CF3C6F4OC6F4CH(C6F5)OH (21) are synthesized by the reactions of 5 with benzaldehyde and pentafluorobenzaldehyde in the presence of tetrabutylammonium fluoride as a catalyst. In the synthesis of 21 the byproduct CF3C6F4OC6F4CH(C6F5)OC6F4CHO (22) is also formed and isolated.

show abstract

“…119 In 1967, the formation of diethyl 4,5,6,7-tetrafluorobenzo [b]thiophen-2,3-dicarboxylate in 49% yield, by the reaction of lithium pentafluorobenzenethiolate with diethyl acetylenedicarboxylate in tetrahydrofuran under reflux, was reported (Scheme 84). 120 Later, the cyclization reaction was shown to occur under very mild conditions (-70°t o -58°C) in 74% yield. 121 A similar reaction of lithium 1,3,4,5,6,7,8-heptafluoro-2-naphthalenethiolate and its isoquinoline analogue with dimethyl acetylenedicarboxylate was reported to give the polyfluorinated condensed products.…”

Section: Scheme 82mentioning

confidence: 99%