A general synthesis of 1-(1-alkenyl)benzotriazoles

Deproto-metallation using a mixed lithium–zinc base and computed CH acidity of 1-aryl 1H-benzotriazoles and 1-aryl 1H-indazoles

“…1-(4-Trifluoromethylphenyl)-1H-benzotriazole (1d) was prepared from benzotriazole (1.2 g) and 1-iodo-4-(trifluoromethyl)benzene (1.8 mL) using the general procedure 1, and was isolated (eluent: 4 : 1 heptane-AcOEt) in 71% yield (1.9 g) as a white powder: mp 168 °C; 1 H NMR (CDCl 3 , 300 MHz) 7.49 (ddd, 1H, J = 8.4, 7.0 and 0.9 Hz), 7.64 (ddd, 1H, J = 8.4, 7.0 and 1.0 Hz), 7.80 (dt, 1H, J = 8.4 and 0.9 Hz), 7.90 (d, 2H, J = 8.4 Hz), 7.99 (d, 2H, J = 8.4 Hz), 8.19 (ddd, 1H, J = 8.4, 1.0 and 0.9 Hz); 13 C{1H} NMR (CDCl 3 , 75 MHz) 110.2 (CH), 120.7 (CH), 122.6 (2CH), 123.8 (q, CF 3 , J = 272 Hz), 124.9 (CH), 127.3 (q, 2CH, J = 4 Hz), 129.0 (CH), 130.5 (C, J = 33 Hz), 132.0 (C), 140.0 (C), 146.8 (C); 19 F{1H} NMR (CDCl 3 , 282 MHz) −63. The NMR data are analogous to those previously described.…”

“…18 One year later, Johnson and coworkers reported similar metallation at the 4 position, but this time from borane-free 1-(alkoxymethyl)benzotriazoles using lithium diisopropylamide at low temperature. 19 Katritzky and co-workers documented in 2003 dianion formations (metallation at both the 7 position and the lateral chain) from benzotriazoles bearing a vinyl chain using butyllithium in THF at −78 °C. 20 In the indazole series, deproto-lithiation only proved possible in the case of 2-substituted 2H-indazoles for which ring opening of 3-lithio derivatives is unlikely.…”

“…Combinations of lithium reagents and softer metal compounds have recently emerged as efficient tools to deprotometallate sensitive aromatic compounds. 21 In the framework of these studies, our group developed efficient pairs of metal amides which complement each other in deproto-metallation † Electronic supplementary information (ESI) available: 1 H, 13 C and 19 F NMR spectra, crystal data, calculated values of the Gibbs energies Δ acid G [kcal mo1 −1 ] for deprotonation at the corresponding positions of the investigated heteroaromatic compounds, and selected Cartesian coordinates of molecular geometry for the most stable rotamer forms of the investigated heteroaromatics (on example of 1e, 2e) (neutral molecule, gas phase) optimized at B3LYP/6-31G(d) level of theory. CCDC 962368-962380.…”

Hypervalent Iodine in Synthesis 73: A New Stereoselective Synthesis of 1-(1-alkenyl) Benzotriazoles by the reaction of Alkenyl(phenyl)iodonium Salts with Benzotriazole

“…15 The synthesis of 1-(1-alkenyl)benzotriazoles is of current interest. 16,17 We now wish to report a simple and convenient method for the synthesis of 1-(1-alkenyl)benzotriazoles by the nucleophilic substitution reaction of benzotriazole anion and vinyl(phenyl)iodonium salts.Recently our research interest is in the chemistry of hypervalent iodine compounds. Because of an excellent leaving group ability of a phenyliodonyl moiety, vinyl(phenyl)iodonium salts undergo nucleophilic vinyl substitutions under mild conditions, thus providing a useful route for the synthesis of various kinds of olefins.…”

“…15 The synthesis of 1-(1-alkenyl)benzotriazoles is of current interest. 16,17 We now wish to report a simple and convenient method for the synthesis of 1-(1-alkenyl)benzotriazoles by the nucleophilic substitution reaction of benzotriazole anion and vinyl(phenyl)iodonium salts.…”