Conversion of Arylboronic Acids to Tetrazoles Catalyzed by ONO Pincer-Type Palladium Complex

Abstract

A convenient synthesis of a library of tetrazoles through a novel and operationally simple protocol effecting the direct conversion of arylboronic acids catalyzed by a new ONO pincer-type Pd(II) complex under mild reaction conditions using the readily available reagents is reported. The palladium complex was reused up to four cycles in an open-flask condition.

One-Pot Suzuki-Hydrogenolysis Protocol for the Modular Synthesis of 2,5-Diaryltetrazoles

“…IR ν max (neat): 3092, 3059, 3003, 2982, 2922, 2851, 1614, 1560, 1522, 1501, 1483, 1452, 1425 cm –1 . Analytical data are in agreement with the literature …”

“…Analytical data are in agreement with the literature. 24 5-(Naphthalen-2-yl)-1H-tetrazole (3g). Synthesized in accordance with the general procedure using 1-benzyl-5-bromo-1H-tetrazole (598 mg, 2.5 mmol), naphthalen-2-ylboronic acid (559 mg, 3.25 mmol), XPhos Pd G3 (63.5 mg, 75 μmol), Evonik P1071 Pd/C (266 mg, 250 μmol), cesium carbonate (1222 mg, 3.75 mmol), water (4.50 mL, 50 mmol), toluene (25 mL), and ethanol (12.5 mL) to yield 5-(naphthalen-2-yl)-1H-tetrazole (331 mg, 1.53 mmol, 61% yield) as a white solid.…”

“…Analytical data are in agreement with the literature. 24 Methyl 4-(1H-Tetrazol-5-yl)benzoate (3m). Synthesized in accordance with the general procedure using 1-benzyl-5-bromo-1Htetrazole (120 mg, 0.5 mmol), (4-(methoxycarbonyl)phenyl)boronic acid (135 mg, 0.75 mmol), XPhos Pd G3 (12.7 mg, 15 μmol), cesium carbonate (326 mg, 1.0 mmol), water (90 μL, 5.0 mmol), toluene (2.5 mL), Evonik P1071 Pd/C (10.6 mg, 10 μmol), and ethanol (1.5 mL) to yield methyl 4-(1H-tetrazol-5-yl)benzoate (20.3 (neat): 3154, 3098, 3073, 3046, 3019, 2953, 2928, 2855, 1709, 1686, 1566, 1499, 1427 cm −1 .…”

Carbonylative Suzuki coupling reactions catalyzed by ONO pincer–type Pd(II) complexes using chloroform as a carbon monoxide surrogate

“…Complexes having different pincer skeleton such as CCC, NNN, CNC, NCN, PNP, SNS, ONO, and SCS have been used in catalysis and materials science. [41][42][43][44][45][46][47][48] In particular, the ONO pincertype palladium complexes have proved to be very effective catalysts for Suzuki-Miyaura coupling, [49] C-2 arylation of quinoline scaffolds, [50] Domino reaction of benzoyl chloride with arylboronic acids, [51] and synthesis of tetrazoles, [52] etc. In recent years, hydrazonebased ONO pincer complexes have also been reported to exhibit interesting biological and catalytic properties.…”

Crystal Structure and Electrochemical Property of Tetrazole Complex of Copper [Cu(pta)2(NO3)2(H2O)2] (pta = 1-Phenyl-1H-tetrazole)

“…For example, l-phenyl-5-mercapto-1,2,3,4-tetrazole is a photosensitive material widely used in domestic and foreign production. Various synthetic methods of tetrazole have been reported [7][8][9][10]. Tetrazolium derivatives have been widely used in medicine and life science due to their unique structure and acid-base characteristics.…”