[3+2]-Cycloaddition of α-Diazocarbonyl Compounds with Arenediazonium Salts Catalyzed by Silver Nitrate Delivers 2,5-Disubstituted Tetrazoles

Abstract

[3+2]-Cycloaddition of arenediazonium salts with diazo compounds (earlier exemplified only for trimethylsilyldiazomethane and 2,2,2-trifluorodiazoethane) has been developed to include a wide range of readily available α-diazocarbonyl compounds. The resulting 2-aryl-5-acyl-2H-tetrazoles are of high value in medicinal chemistry.

Recent Advances in the Synthesis of Nitrogen Heterocycles Using Arenediazonium Salts as Nitrogen Sources

“…A silver‐catalyzed [3+2] cycloaddition of α ‐diazocarbonyl compounds with arenediazonium tosylates was also reported by Krasavin and co‐workers (Scheme 40). [52] The arenediazonium tosylates which were used directly as obtained in the crude form from the diazotization reaction, reacted with diazocarbonyl compounds using 10 mol% AgNO 3 as the catalyst to generate various 2‐aryl‐5‐acyl‐2 H ‐tetrazoles in moderate to good yields with a broad substrate scope.…”

From Rare Reagents to Rare Products: Regiospecific Silver‐Catalyzed [3+2] Cycloaddition of Aryl‐, Alkyl‐ and Aminosulfonyl Diazomethanes with Arenediazonium Tosylates

“…Both 2 and 3 appeared suitable partners for a [3+2] cycloaddition reaction with arenediazonium salts. As reported recently by us and others such a reaction, catalyzed by silver(I) salts, provides a facile and regiospecific entry into medicinally important 2,5‐disubstituted tetrazoles. We reasoned that this cycloaddition, if successfully applied towards 2 and 3 , would deliver 2‐aryl tetrazol‐5‐yl sulfones 4 and sulfonamides 5 (Figureà).…”

“…Sulfonyl diazomethanes 2a – h , along with three sulfamoyl diazomethanes 3a – c prepared as described recently, were employed in the cycloaddition reactions with a series of arenediazonium tosylates 6a – k (Figureà) which had earlier been found to be stable and easy to handle non‐hygroscopic solid reagents and, importantly, proven efficient partners in similar cycloaddition reactions with acyl diazomethanes …”

“…Reaction conditions identified earlier for the cycloaddition of arenediazonium tosylates 6a – k with acyl diazomethanes (1.1 equiv. 6 , 10 mol‐% AgNO 3 , DABCO, 10 % DMF in THF, 0 °C to r. t., 18 h) were found to give high yields of the desired cycloaddition products and, therefore, were not optimized further. These conditions were employed throughout the scope investigation the results of which are presented in Schemeà.…”

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

“…also reported the synthesis of 2‐aryl‐2 H ‐tetrazoles 159 via the [3 + 2] cycloaddition reaction of aryl diazonium salts with trimethylsilyldiazomethane (TMSCHN 2 ) by using excess silver salt and caesium fluoride (Scheme 40e). [ 191 ] Given the broad applicability and practicality of this tactic, there is no doubt that these reactions will find wide implications in tetrazole chemistry, meanwhile in‐depth mechanistic study and divergent regio‐control are also suggested to be put on the agenda. [ 192,193 ]…”