Nucleophilic addition of secondary phosphine chalcogenides to, α,β-acetylenic γ-hydroxy acid nitriles and a rearrangement of the adducts

Bis(2-phenylethyl)phosphine oxide and sulfide and bis[2-(2-pyridyl)ethyl]phosphine sulfide add easily (LiOH–THF, 28–30°C) to 4-hydroxy-4-methyl-2-pentynenitrile to give regio- and stereoselectively 3-substituted (Z)-4-hydroxy-4-methyl-2-pentenenitriles in 82–91% yield; the latter, upon heating (58–60°C) in the presence of LiOH in THF, rearrange cleanly to the corresponding 3-cyano-2-propen-1-yl phosphinates and phosphinothioates (isolated yields of 82–86%).