o-Iodoxybenzoic Acid- and Tetraethylammonium Bromide-Mediated Oxidative Transformation of Primary Carboxamides to One-Carbon Dehomologated Nitriles

Abstract

A clean and efficient method for the oxidative transformations of primary carboxamides to one-carbon dehomologated nitriles using the combination of o-iodoxybenzoic acid and tetraethylammonium bromide has been developed. This method exhibits a broad scope and is expected to be of great utility in organic synthesis.

2‐Iodoxybenzoic Acid—A Simple Oxidant with a Dazzling Array of Potential Applications

“…[223] When the same reaction conditions are applied to a-monosubstituted primary amides, dehomologation with loss of one carbon atom is also observed, although in this case with formation of nitriles. [224] The reaction of cis-2,4-enyn-1ols with IBX leads to the formation of 2-acyl furans. [225] Thioamides dimerize to 1,2,4-thiadiazoles in an oxidative cyclization mediated by IBX.…”

Rearrangements Induced by Hypervalent Iodine

“…However, some authors have described rearrangements promoted by an iodine(V) oxidant. For example, when reacted with IBX in the presence of Et 4 NBr, amides 136 undergo a Hofmann-type rearrangement to produce cyanides 137 (Scheme 39) [32]. Tertiary alcohols 138a and 138b can be rearranged to form enones 139a and 139b (Scheme 40).…”

2‐Iodoxybenzoesäure – ein einfaches Oxidationsmittel mit einer Vielfalt an Anwendungsmöglichkeiten

“…[223] Identische Reaktionsbedingungen führen bei einfach a-substituierten primären Amiden ebenfalls zur Kettenverkürzung unter Verlust eines Kohlenstoffatoms, allerdings unter Bildung von Nitrilen. [224] Die Umsetzung von cis-2,4-Enin-1-olen mit IBX führt zur Bildung von 2-Acylfuranen. [225] Thioamide können durch oxidative Cyclisierung mit IBX zu 1,2,4-Thiadiazolen dimerisieren.…”