Electrochemical Alkynyl/Alkenyl Migration for the Radical Difunctionalization of Alkenes

Abstract

An efficient electrochemical 1,2-sulfonylation/alkynylation of alkenes via radical 1,4-alkynyl migration of alkynyl-substituted tertiary alcohols is described, which used sodium sulfinates as sulfonyl sources affording the corresponding α-sulfonyl-β-alkynylated products in moderate to excellent yields. This electrochemical reaction proceeds smoothly without the use of any metal catalyst, additive and oxidant and thus represents a new and eco-friendly strategy for the difunctionalization of unactive olefins, and also the first example of the electrochemical distal radical migration reaction.

Electrocatalytic Oxidative Transformation of Organic Acids for Carbon–Heteroatom and Sulfur–Heteroatom Bond Formation

“…In 2018, Han and co‐workers reported an electrochemical 1,2‐sulfonylation/alkynylation of alkenes through radical 1,4‐alkynyl migration of alkynyl‐substituted tertiary alcohols (Scheme ) . Aryl‐ and alkyl‐substituted sodium sulfinates were used as the sulfonyl source in this reaction.…”

“…Various sulfonated functionalized heteroarenes were prepared in an undivided cell, avoiding the use of any metal catalysts, additives, or external chemical oxidants. A sulfonyl radical initiated mechanism, similar to that reported by Han and co‐workers, was proposed.…”

“…kynyl migration of alkynyl-substituted tertiary alcohols (Scheme 38). [41] Aryl-and alkyl-substituted sodium sulfinates were used as the sulfonyl source in this reaction. Apart from 1,4-alkynyl migration, 1,4-alkenyl migration was also demonstrated.T he reactionp roceeds smoothly in an undivided cell withoutt he use of any metal catalyst, additive, or external chemical oxidant.…”

Recent Advances in Electrochemical Chalcogen (S/Se)‐Functionalization of Organic Molecules

“…An electrochemical 1,2‐sulfonylation/alkynylation of alkenes via radical 1,4‐alkynyl migration of alkynyl‐substituted tertiary alcohols was described by Pan and co‐workers . Sodium sulfinates were used as sulfonyl sources, affording the corresponding α‐sulfonyl‐β‐alkynylated products.…”

“…An electrochemical 1,2-sulfonylation/alkynylation of alkenes via radical 1,4-alkynyl migration of alkynyl-substituted tertiary alcohols was described by Pan and co-workers. [110] Sodium sulfinates were used as sulfonyl sources, affording the corresponding α-sulfonyl-β-alkynylated products. With carbon elec-trodes, the reaction occurs at a constant current density of 2 mA/cm 2 in CH 3 Control experiments were performed and when the radical inhibitor TEMPO was added the reaction was inhibited.…”