Abstract: | Alkyl vinyl selenides react with diverse secondary phosphines and elemental selenium in a 1.1:1:2 molar ratio (120–124°C, 20–40 min, 1,4‐dioxane) to afford selectively earlier unknown diselenophosphinic Se‐esters, R2P(Se)SeCH(Me)SeR´, in 82–99% yield. This three‐component atom‐economic reaction proceeds via intermediate formation of diselenophosphinic acid R2P(Se)SeH (generated from secondary phosphine and selenium), which adds to the double bond of vinyl selenide in a Markovnikov manner to give the target products. |