Microwave-Assisted Metal-Free Synthesis of Vinyl Sulfoxides Using DMSO as Solvent and Reagent

Among organosulfur compounds, sulfoxides play a crucial role in many biologically active substances with a diverse range of applications in natural products, pharmaceuticals, agrochemicals, and materials. We have developed an efficient microwave-assisted method for synthesizing vinyl sulfoxides through oxidative condensation of easily accessible aromatic aldehydes or benzyl alcohols with dimethyl sulfoxide (DMSO), using a base under ambient conditions. In this method, DMSO serves a dual purpose: it acts as a source of the (methylsulfinyl)methyl group (─CH₂SOMe) and functions as a solvent. This protocol is highly tolerant of various aromatic aldehydes, including heteroaryl and α,β-unsaturated aldehydes, yielding corresponding vinyl sulfoxides in good to excellent yields. Additionally, this methodology can also be applied to synthesize various vinyl sulfoxides from benzyl alcohols, yielding moderate to good results. The advantages of this strategy include being metal-free, requiring short reaction times, maintaining mild conditions, operational simplicity, high selectivity, and achieving moderate to excellent yields.