Halogen and chalcogen cation pools stabilized by DMSO. Versatile reagents for alkene difunctionalization

Area of Science:

• Electrochemistry
• Computational Chemistry
• Organic Synthesis

Background:

• Halogen and chalcogen cations are reactive species.
• Stabilization of these cations is crucial for their application.
• Dimethyl sulfoxide (DMSO) is a common solvent in electrochemical studies.

Purpose of the Study:

• To generate and stabilize halogen and chalcogen cations (X+) using low-temperature electrochemical oxidation.
• To investigate the stabilizing effect of dimethyl sulfoxide (DMSO) on these cations.
• To explore the synthetic utility of these stabilized cation pools in organic reactions.

Main Methods:

• Low-temperature electrochemical oxidation for cation generation.
• Density Functional Theory (DFT) calculations for stability analysis.
• Cold-spray-ionization mass spectrometry (MS) for complex observation.
• Reactions with alkenes, aminoalkenes, and 1,6-dienes for synthetic applications.

Main Results:

• Stable pools of Br+, I+, ArS+, and ArSe+ cations were generated and accumulated in DMSO.
• DFT calculations confirmed DMSO's stabilizing effect through coordination.
• Complexes of I+ with DMSO were observed via MS.
• Cation stability order was determined: Br+ < I+ < ArS+ < ArSe+.
• The cation pools reacted with alkenes to form β-X-substituted alkoxysulfonium ions, convertible to carbonyl compounds or alcohols.
• Cyclization reactions were achieved with aminoalkenes and 1,6-dienes.

Conclusions:

• Low-temperature electrochemical oxidation in DMSO provides a method for generating and stabilizing reactive halogen and chalcogen cations.
• DMSO plays a key role in stabilizing these cations through coordination.
• The generated cation pools are versatile reagents for synthesizing functionalized organic molecules, including carbonyl compounds, alcohols, and cyclic products.