Phosphenium-Komplexe, XXIX [1]. [4+2]-Cycloadditionen von Phospheniumkomplexen des Typs Cp(OC)₂W = PR₂(R = Alkyl, Aryl) mit 2,3-Dimethylbutadien / Phosphenium Complexes, XXIX [1], [4+2]-Cycloaddition of Phosphenium Complexes of the Type Cp(OC)₂W=PR₂ (R = Alkyl, Aryl) with 2,3-Dimethylbutadiene

Abstract

The structure of 4a has been determined by X-ray diffraction.

Phosphaalkenes R1C(O)–P=C(NMe2)2 (R1=Ph, 4‐EtC6H4): Versatile Reagents for 1,3‐Dipolar Cycloadditions to Phosphenium Complexes [Cp(CO)2M = PPh2] (M = Mo, W)

“…The purpose of this work was to study the reactivity of the P ‐benzoylphosphaalkenes PhC(O)P=C(NMe 2 ) 2 ( 3 )6 and 4‐EtC 6 H 4 C(O)P=C(NMe 2 ) 2 ( 5 ) with the phosphenium complexes [Cp(CO) 2 M = PPh 2 ] ( 2a : M = Mo; 2b : W). The latter were generated in situ by the dehydrochlorination of the functionalized phosphane complexes [Cp(CO) 2 ClMP(H)Ph 2 ]7 ( 1a : M = Mo; 1b : W) with diazabicycloundecene (DBU). Phosphaalkene 5 was synthesized as a yellowpowder in 81 % yield from 4‐ethylbenzoylchloride andMe 3 SiP=C(NMe 2 ) 2 8 (Scheme ).…”

“…A 1,4,2‐diphosphaoxabuten‐3‐yl ligand chelates the tungsten atom through bonds W(1)–P(1) [2.3632(5) Å] and W(1)–P(2) [2.5556(5) Å]. The former bond length is slightly shorter than the coordinative W–P bond in 7 [2.432(2) Å]7 or 8 [2.434(2) Å] 14…”

“…Solvents were carefully dried with an appropriate drying agent and freshly distilled under an atmosphere of N 2 before use. The following compounds were prepared according to literature procedures: [Cp(CO) 2 ClMo–PHPh 2 ] ( 1a ),7 [Cp(CO) 2 ClW–PHPh 2 ] ( 1b ),7 PhC(O)P=C(NMe 2 ) 2 ( 3 ),6 and Me 3 SiP=C(NMe 2 ) 2 8. Diazabicycloundecene (DBU), 4‐EtC 6 H 4 C(O)Cl, and Florisil (0.150–0.250 mm) were purchased commercially.…”