Oxidative Radical Transnitrilation of Arylboronic Acids with Trityl Isocyanide

Abstract

We report a radical transnitrilation of arylboronic acids with trityl isocyanide in the presence of manganese(III) acetate. Many functional groups can be tolerated in this transformation, and a special positive effect of benzoic acid in this reaction has been observed.

Cyanation with isocyanides: recent advances and perspectives

“…38 The results obtained in this In 2022, Li and co-workers disclosed an oxidative radical cyanation of arylboronic acids with triphenylmethyl isocyanide for the synthesis of diverse aryl nitriles (Scheme 27). 39 In this transformation, a range of aryl boronic acids that contained electron-donating or electron-with drawing groups were formed in moderate-to-high yields. Interestingly, the addition of benzoic acid could greatly improve the yields.…”

“…Their versatility has been witnessed in transition-metal-catalyzed isocyanide insertion, 10 isocyanide-based multicomponent reactions, 11 and radical isocyanide chemistry, 12 resulting in the rise of imidoylation, 13 ketenimination, 14 and cyanation. 15–53 Among the innumerable applications of isocyanides, the most striking feature is their ability to act as a “cyano” source, where they show advantages over other sources in being nontoxic, commercially available, easy to handle, and environmentally benign. In general, three types of cyanation with isocyanides have been established.…”

Recent investigations into deborylative (thio-/seleno-) cyanation of aryl boronic acids

“…Very recently, a beautiful and efficient manganese-mediated cyanation of (hetero)aryl boronic acids 41 with commercially available trityl isocyanide 42 as cyanating agent using the system comprising of cheap and non-toxic Mn(OAc) 3 ·2H 2 O as mediator and benzoic acid as an additive was developed by Li and coworkers. 56 As shown in Scheme 17a , a wide range of ortho -, meta -, and para -substituted aryl boronic acids with diverse steric and electronic properties were amenable in this reaction, rendering the respective nitriles 43 in modest to excellent yields. However, alkenyl- and alkylboronic acids were incompatible in the reaction and applicability of boronic esters as starting materials was not investigated in this study.…”

A Mn(iii)-catalyzed arylboronic acid-based cascade reaction via a nonclassical organometallic-radical mechanism

“…It should be noted that usually manganese( iii ) salts are not favorable for transmetallation with arylboronic acids to produce Ar–Mn( iii ) species due to their strong oxidizing ability, but there are some reports which supposed that arylboronic acid might undergo in situ transmetalation with Mn( iii ) to form Ar–Mn( iii ) species followed by the loss of Mn( ii ) to give the corresponding aryl radical. 8…”