Electrochemical Benzylic C(sp³)–H Acyloxylation

Abstract

The development of sustainable C(sp 3 )–H functionalization methods is of great interest to the pharmaceutical and agrochemical industries. Anodic oxidation is an efficient means of producing benzylic cations that can undergo subsequent in situ nucleophilic attack to afford functionalized benzylic products. Herein, we demonstrate the suitability of carboxylic acids as nucleophiles to yield benzylic esters. This method employs a series of secondary benzylic substrates and functionalized carboxylic acids and is demonstrated on a gram scale in flow.

Benzylic C(sp3)–H Bonds Play the Dual Role of Starting Material and Oxidation Inhibitor for Hydrazides in the Electrochemical Synthesis of Hydrazones

“…As shown in Figure S4, the electrochemical oxidation peak of benzyl alcohol for conversion to benzaldehyde appears as previously reported. , Also, in the blank sample, we did not observe any oxidation peak near 2 volts; thus, the oxidation peak near 2 volts can be attributed to benzyl alcohol. Similarly, in CVs of aryl halides, an oxidation peak appears in the same voltage associated with the electrochemical generation of benzyl alcohol on the electrode surface. , Further, we identified the oxidation peak of benzyl alcohol in the CV of toluene. − The cyclic voltammogram of tosyl hydrazide was first recorded in water. However, due to its low solubility in water, the oxidation peak was not clearly observed.…”

eFluorination using cheap and readily available tetrafluoroborate salts

“…Indeed, benzylic positions are known to be easily oxidisable under electrochemical conditions and are often problematic. 35,36 Pleasingly, only traces of benzylic oxidation (aldehydes and benzylic alcohols) were observed the crude electrolysis mixtures of 2j and 2l. The incorporation of aromatic halides (2k,m,n,o,t) had little effect on the fluorination.…”

Study of the Electrochemical Behavior of N-Substituted-4-Piperidones Curcumin Analogs: A Combined Experimental and Theoretical Approach

“…Based on the above, in this work we propose to study the electrochemical behavior of N-substituted-4-piperidone curcuminoid analogs ( Table 1 ). The effect of different substituents on the aromatic rings and the variation in the N-substituent of the piperidone ring (methyl and benzyl) could help in the understanding of the electrochemical behavior and help in the design of curcumin piperidone derivatives with biological activity, besides determining the oxidation potentials that could be useful in obtaining derivatives by electrochemical synthesis [ 29 , 30 , 31 ]. We employ differential pulse and cyclic voltammetry to experimentally study the electrochemistry of compounds, and DFT calculations to obtain theoretical redox potentials, which are then compared with those obtained experimentally, assessing the effects of the substituents at the phenyl substituent.…”