New Organophosphorus Ligands: Cyclopropanation and Other Reactions of Cumulenes Bearing Diphenylphosphanyl Substituents

Hydrophosphorylation of 1,4‐bis(diphenylphosphanyl)butadiyne with diphenylphosphane leads to the butadiene (Ph₂P)₂CCHCHC(PPh₂)₂ (1). Treatment of 1 with dimethylsulfonium methylide gives the vinylcyclopropane (Ph₂P)₂CCHCH(CH₂)C(PPh₂)₂ (2). Compound 2 reacts with aqueous hydrogen peroxide, elemental sulfur, or selenium to afford the tetrachalcogenides (Ph₂XP)₂CCHCH(CH₂)C(PXPh₂)₂ with X = O (3), X = S (4), X = Se (5), respectively. While the tetraphosphane 1 and the vinyl‐cyclopropane compound 2 cannot be converted into a bis‐(cyclopropyl) compound with an excess of Me₂SCH₂, the tetrasulfide 4 readily affords a mixture of (1R,1′R)‐/(1S,1′S)‐and meso‐2,2,2′,2′‐tetrakis(diphenylthiophosphinyl)‐1,1′‐bicyclopropyl (6, 7) in good yield. Treatment of 1,1,4,4‐tetrakis‐(diphenylphosphanyl)butatriene with dimethylsulfonium methylide leads to the vinylidenecyclopropane (Ph₂P)₂CCC(CH₂)C(PPh₂)₂ (8). Compound 8 is converted into its tetrasulfide (Ph₂SP)₂CCC(CH₂)C(PSPh₂)₂ (9) by treatment with elemental sulfur. The crystal structures of 1, 2, 4, 7, and 8 have been determined by single‐crystal X‐ray diffraction.