Electrochemically Induced Thiocyanation of Enaminones: Synthesis of Functionalized Alkenes and Chromones

Abstract

A simple and efficient electrochemically induced thiocyanation of enaminones under undivided electrolytic conditions has been developed. With this protocol, various polyfunctionalized alkenes and chromones could be obtained in good to excellent yields using readily available KSCN as the thiocyanation reagent under catalyst-, oxidant-, and transition-metal-free conditions.

Electrochemical Oxidative Cross‐Coupling of Enaminones and Thiophenols to Construct C−S Bonds

“…Zeng, [6b] Xu, [6c] Mei, [6d] and other groups [6e–k] also did related works, respectively. In 2019, Zan Yang et al reported electrochemically induced thiocyanation of enaminones [6l] . As part of our continuing study on electrosynthesis, herein, we report an efficient and facile method to construct alkenyl sulfur compounds by electrochemical anodic oxidation method.…”

One-Pot Synthesis of 5-Acyl-1,2,3-Thiadiazoles from Enaminones, Tosylhydrazine, and Elemental Sulfur under Transition-Metal-Free Conditions

“…Enaminones, an important class of readily available and inexpensive precursors, have been used as valuable synthetic building blocks and found broad applications in various organic and medicinal syntheses . On the other hand, elemental sulfur as the [S] source for the synthesis of sulfur-containing organic compounds has attracted considerable interest .…”

Recent Advances in Organic Synthesis Based on N,N-Dimethyl Enaminones

“…8 Interestingly, when Ru(bpy) 3 Cl 2 •6H 2 O was employed as the photoredox catalyst, the -thiocyanation reaction provided NH 2 -functionalized thiocyanated enamines through a further amino-exchange process. Shortly afterwards, Zhou and co-workers disclosed a similar -thiocyanation of N,N-dimethyl enaminones in the presence of KSCN using an undivided cell under electrolytic conditions 9 or with PhI(OAc) 2 as an oxidant, 10 respectively. These -thiocyanation reactions were proved to occur via a free-radical pathway.…”

“…In 2019, Zhou and co-workers reported the synthesis of 3-thiocyanyl chromones via both electrochemistry-induced thiocyanation of N,N-dimethyl enaminones using an undivided electrolytic cell and PIDA-mediated thiocyanation of enaminones in water at room temperature (Scheme 62). 9,10 Nevertheless, these two reaction processes involved the addition of a thiocyanyl free radical to the enaminone under the different oxidative conditions. Furthermore, various thiocyanyl chromones could be obtained in good to excellent yields with diverse functional groups using these protocols.…”