The Synthesis of 1,3-Dithiole Derivatives by Using Bun3P·CS2 Adduct

The red crystalline adducts formed between trialkylphosphines and carbon disulfide were confirmed to be l,3-dipolar structure by X-ray diffraction in 1961.^1] Despite the apparent synthetic potential of the 1,3-dipolar structure, studies on its cycloaddition have only been restricted in electron-deficient alkynes as dipolarophiles.^2-5] However, reactions with electron-rich alkynes have received little attention.