Sequential Pd(0)/Fe(III) Catalyzed Azide–Isocyanide Coupling/Cyclization Reaction: One-Pot Synthesis of Aminotetrazoles

Abstract

A rapid and efficient synthesis of aminotetrazole from aryl azides, isocyanides, and TMSN is developed. The reaction is promoted by sequential Pd(0)/Fe(III) catalysis. The reaction sequence utilizes the Pd-catalyzed azide-isocyanide denitrogenative coupling reaction to generate unsymmetric carbodiimide in situ, which reacts with TMSN in the presence of FeCl in a single pot. The methodology has distinct advantages over traditional synthetic approaches where toxic Hg and Pb salts are employed at stoichiometric scale.

Transition‐Metal‐Catalyzed Cross‐Coupling and Sequential Reactions of Azides with Isocyanides

“…In 2018, this group developed a sequential Pd(0)/Fe(III)‐catalyzed three‐component assembly of aryl azides, isocyanides, and trimethylsilyl azide (TMSN 3 ) to synthesize aminotetrazoles (Scheme 18). [29] By controlling the order in which the catalysts are added, the Pd‐catalyzed azide−isocyanide coupling process and the FeCl 3 ‐promoted intermolecular cyclization were sequentially realized. The proposed mechanism is shown in Scheme 18.…”

Recent Advances in Palladium-Catalyzed Isocyanide Insertions

“…In the same year, Ding et al reported multiple one-pot post-imidoylation cascade transformations based on similar starting materials [91]. This group further expanded the follow-up chemistry in a one-pot process [92]. The initial nitrene transfer of azide precursors 186 to isocyanides 5 under Pd catalysis proceeds in yields up to 90%.…”

“…This transformation tolerates tertiary, secondary, and aromatic isocyanides affording the corresponding aminotetrazole 187 with full regioselectivity in good to excellent yields. However, only starting materials are isolated if aliphatic azides are This group further expanded the follow-up chemistry in a one-pot process [92]. The initial nitrene transfer of azide precursors 186 to isocyanides 5 under Pd catalysis proceeds in yields up to 90%.…”

“…However, only starting materials are isolated if aliphatic azides are employed. This group further expanded the follow-up chemistry in a one-pot process [92]. The initial nitrene transfer of azide precursors 186 to isocyanides 5 under Pd catalysis proceeds in yields up to 90%.…”

Synthesis of 1-(para-methoxyphenyl)tetrazolyl-Substituted 1,2,3,4-Tetrahydroisoquinolines and Their Transformations Involving Activated Alkynes

“…There are many examples of isonitriles in multicomponent reactions for forming original biologically-active compounds [1,2]. They are widely used in green chemistry [3,4,5] and in the synthesis of tetrazoles [6,7,8,9,10,11]. Substituted or heterocyclic annulated tetrazoles have an extensive range of biological activity.…”