Regioselective and Stereoselective Addition of Tetrazole Derivatives to Electron‐poor Acetylenic Esters in the Presence of Triphenylphosphine

Abstract

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and acetylenic esters by tetrazole derivatives leads to the formation of vinyltriphenylphosphonium salts. The cation of these salts undergoes an addition reaction with the counter anion in CH2Cl2 at room temperature to yield the corresponding stabilized phosphorus ylides. Elimination of triphenylphosphine from the stabilized phosphorus ylides leads to the corresponding electron‐poor N‐vinyl tetrazoles in fairly high yields. Structures of N‐vinyl tetrazoles were determined by IR, 1H NMR, 13C NMR and single crystal X‐ray structure analyses. The reaction is fairly regioselective and stereoselective.

Molecular Structure, NMR, FMO, MEP and NBO Analysis of ethyl-(Z)-3-phenyl-2-(5-phenyl-2H-1,2,3,4-tetraazol-2-yl)-2-propenoate Based on HF and DFT Calculations

“…Recently, we have established a one-pot method for the synthesis of organophosphorus compounds [17][18][19]. We have reported the regioselective and stereoselective preparation of electron-poor N-vinyl tetrazoles from the acetylenic esters and 5-benzyl-2H-tetrazole in the presence of triphenylphosphine and the structure of one of the products, namely compound ethyl-(Z)-3-phenyl-2-(5-phenyl-2H-1,2,3,4-tetraazol-2-yl)-2-propenoate was confirmed by single-crystal X-ray analysis [20]. In the present work, we investigate the energetic and structural properties of crystal structures ethyl-(Z)-3-phenyl-2-(5-phenyl-2H-1,2,3,4-tetraazol-2-yl)-2-propenoate [20] using the HF and DFT calculations.…”

“…We have reported the regioselective and stereoselective preparation of electron-poor N-vinyl tetrazoles from the acetylenic esters and 5-benzyl-2H-tetrazole in the presence of triphenylphosphine and the structure of one of the products, namely compound ethyl-(Z)-3-phenyl-2-(5-phenyl-2H-1,2,3,4-tetraazol-2-yl)-2-propenoate was confirmed by single-crystal X-ray analysis [20]. In the present work, we investigate the energetic and structural properties of crystal structures ethyl-(Z)-3-phenyl-2-(5-phenyl-2H-1,2,3,4-tetraazol-2-yl)-2-propenoate [20] using the HF and DFT calculations. The optimized geometry, 1H and 13C NMR analysis, frontier molecular orbitals (FMO), detail of quantum molecular descriptors, molecular electrostatic potential (MEP), natural charge and NBO analysis of the title compound were calculated.…”

“…X-ray diffraction analysis of the studied compound shows that the structure is stabilized by intramolecular hydrogen bond. According to experimental results is obtained [20], it revealed that the title molecule has two intramolecular hydrogen bonds (see Fig. 1 (a)).…”

“…In intramolecular C7-H30…O4 hydrogen bond, the experimental value of bond length H30…O4 are 2.36Å, whereas the calculated values by HF and B3LYP methods are 2.30Å and 2.31Å respectively, that suggesting the a Taken from Ref. [20].…”

“…As seen from Table 2, the bond angel of C19-C20-C21 of phenyl ring in the X-ray and by HF and B3LYP methods is 106.78°, 106.4° and 107.0° respectively 120.13°, 120.1° and 120.1° respectively, which they are close to the typical hexagonal angle of 120°. In addition, the hydrogen bonds length values of experimental [20] and theoretical of the title compound summarized in Table 3. X-ray diffraction analysis of the studied compound shows that the structure is stabilized by intramolecular hydrogen bond.…”