An Improved Synthesis of Vinyl- and β-Iodovinyl Sulfones by a Molecular Iodine-Mediated One-Pot Iodosulfonation-Dehydroiodination Reaction

Abstract

An improved one-pot method to synthesize vinyl sulfones from unsaturated systems by using molecular iodine/sodium arenesulfinate/sodium acetate as reagents was described. Vinyl sulfones derived from styrene derivatives were generally obtained in good to excellent yields except for those bearing strong electron releasing substituent. Aliphatic alkenes and activated alkenes gave the corresponding vinyl sulfone products in moderate to good yields. Arylacetylenes yielded the respective β-iodovinyl sulfones in good yields while low yield was observed with aliphatic terminal alkyne. The potentials of the method entail simplicity, short reaction time, non-anhydrous reaction conditions, employing inexpensive, non-metallic reagent and integrating two reactions that are commonly accomplished separately into a single operation.

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GRAPHICAL ABSTRACT

Keywords:

• Alkenes
• alkynes
• iodine
• sulfur
• vinyl sulfones

ACKNOWLEDGMENTS

Financial support from the Thailand Research Fund (TRF; DBG5480817), Center of Excellence for Innovation in Chemistry (PERCH-CIC), and Mahidol University under the National Research Universities Initiative is gratefully acknowledged.

Notes

^a All reactions were performed using 4-chlorostyrene (0.5 mmol), iodine (1.5 equiv), p-TolSO₂Na (3.0 equiv), and base (1.5 equiv).

^a All reactions were performed using styrene derivative (0.5 mmol).

^b Isolated yields.

^c Product 2i′ was obtained in 33%.

^a All reactions were performed by using alkene (0.5 mmol).

^b Isolated yields.

^c (1) p-TolSO₂Na and I₂ were premixed in acetonitrile (15 min) before cyclohexene (0.5 mmol) in acetonitrile was added, reflux, 1 h then NaOAc (1.5 equiv), reflux, 30 min; (2) DBU (1.5 equiv, acetonitrile, rt, 30 min.

^d The reaction of 1-octene (3a) with iodine in methanol followed by treatment with methanolic potassium hydroxide gave the corresponding vinyl sulfone in 38% yield.

^a All reactions were performed by using activated alkene (0.5 mmol).

^b Isolated yields.

^c The reaction of n-butyl acrylate (5a) with iodine in methanol followed by treatment with methanolic potassium hydroxide failed to provide the corresponding vinyl sulfone.

^a All reactions were performed using alkyne (0.5 mmol).

^b Isolated yields.