Phosphiranes as Ligands: Tungsten(0) and Palladium(0) Complexes of Phosphirano[1,2-c][1,2,3]diazaphospholes

✍ Scribed by Stefan Maurer; Christian Burkhart; Gerhard Maas

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 470 KB
• Volume: 2010
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.201000102

✦ Synopsis

Abstract

Phosphirano[1,2‐c][1,2,3]diazaphospholes 5, which feature a strongly pyramidalized phosphorus atom at a ring fusion position, were identified as a new type of phosphane ligands for transition metals. The derivatives 5a–c smoothly form W(CO)~5~ complexes, which are thermally quite stable – in contrast to the known lability of various carbonylmetal complexes of simple phosphiranes. In the temperature range 120–150 °C, they undergo a clean decomplexation in toluene solution. Bicyclic phosphiranes 5a and 5b, but not the acceptor‐substituted derivative 5c, readily react with the [(E,E)‐dibenzylideneacetone]palladium(0) complex Pd~2~(dba)~3~·CHCl~3~ to form the corresponding isolable complexes [(5a)~2~(dba)Pd] and [(5b)~2~(dba)Pd]. In agreement with the formation of these complexes, it was found that 5a,b as ligands effectively promote the Suzuki cross‐coupling of 4‐bromotoluene with benzeneboronic acid. The solid‐state structure of bicyclic phosphirane 5b and of the complexes [(5a)(CO)~5~W], [(5b)~2~(dba)Pd] (pentane solvate) and [(5b)~2~(dba)Pd] (benzene solvate) were determined by X‐ray diffraction analysis.