Combination of Tetrabutylammonium Iodide (TBAI) with tert‐Butyl Hydroperoxide (TBHP): An Efficient Transition‐Metal‐Free System to Construct Various Chemical Bonds

Abstract

In this account, we describe our recent progress on transition-metal-free-catalyzed cross-coupling reactions using tetrabutylammonium iodide (TBAI) as the catalyst and tert-butyl hydroperoxide (TBHP) as the oxidant. A rich variety of important organic compounds including α-acyloxy ethers, tert-butyl peresters, allylic esters, amides, α-amino nitriles, fully substituted pyrazoles, N-sulfonyl formamidines, α-amino acid esters, cyanomethyl esters, N-nitrosamines, and 3-acyloxy-2,3-dihydrobenzofurans have been successfully achieved in high chemoselectivity. Mechanistic studies suggested that TBAI could decompose TBHP to BuO and BuOO or be oxdized to (hypo)iodite by TBHP.

Synthesis of γ-Lactones by TBAI-Promoted Intermolecular Carboesterification of Carboxylic Acids with Alkenes and Alcohols

“…Based on the abovementioned results and previous studies from the literatures, we formulated a plausible mechanism for this transformation, which is depicted in Scheme . Initially, I – promotes the decomposition of TBHP to generate t BuO • radical and t BuOO • radical The α-hydroxy carbon radical A was generated in situ from isopropyl alcohol under the oxidative conditions.…”

“…In particular, catalytic carbon radical formation from alcohols has attracted much attention in organic synthesis . Although photoinitiated techniques and redox systems have been used as a frequent methods for the generation of carbon radicals from alcohols. , It is still highly valuable to develop more simple and efficient reaction models involving carbon radical from alcohols promoted by tetrabutylammonium iodide (TBAI)/ tert -butyl hydroperoxide (TBHP) catalytic system …”

Iodine‐Catalyzed or ‐Mediated Reactions in Aqueous Medium

“…Conceptually, iodine is a mild oxidizing agent and can be used selectively in many organic syntheses. Before experiencing abundant iodine catalyzed organic synthetic methodology, the advantages of the use of iodine as compared to other halogens and transition metal catalysts are summarized below: [37–50] …”

“…[33][34][35][36] Conceptually, iodine is a mild oxidizing agent and can be used selectively in many organic syntheses. Before experiencing abundant iodine catalyzed organic synthetic methodology, the advantages of the use of iodine as compared to other halogens and transition metal catalysts are summarized below: [37][38][39][40][41][42][43][44][45][46][47][48][49][50] I. Like transition metal catalyst iodine also exists in different oxidation states such as À 1, 0, + 1, + 3, + 5 and + 7 in various inorganic and organic derivatives.…”

Synthesis of N-alkoxyphthalimide derivatives via PIDA-promoted cross dehydrogenative coupling reaction

“…Considering the fact that these strategies are not environmentally friendly, 9 therefore, great efforts have been devoted to develop metal-free free oxidative functionalization of C(sp 3 )–H bond. Tetrabutylammonium iodide (TBAI)/ tert -butyl hydroperoxide (TBHP) has been proved as an efficient transition-metal-free system to apply in C(sp 3 )–H bond functionalization, 10 especially through cross dehydrogenative coupling (CDC), which could assemble complicated molecules from the widely available and simple materials. 11 For example, Prabhu reported a TBAI-catalyzed α-aminoxylation of ketones using TBHP as oxidant to directly construct corresponding N -alkoxyphthalimide products ( Scheme 1b ).…”