Dibenzophospholes synthesis

Application of the Wittig reaction of a nonstabilized ylide to the synthesis of an ( )-alkene is practically and effectively carried out by the Schlosser modification. Alternatively, the use of a trialkylphos-phonium ylide can produce high ratios of ( )-alkene." Recently, Vedejs has developed a reagent using dibenzophosphole ylides (110) to synthesize ( )-disubstituted alkenes (111) fixnn rddehydes (equation 24). The initial addition of ylide occurs at -78 C, but the intermediate oxaphosphetane must be heated to induce alkene formation. The stereoselectivity in the process is excellent, particularly for aldehydes with branched substitution a to the reacting center. Both the ethyl and butyl yli s have b n utilized. 

Warren has also studied dibenzophosphole oxides. The ketophosphine oxide (230) substrate can be formed and selective reduction to either the erythro (233) or the threo (231) adducts carried out. The normal NaBH4 conditions were used for reduction to the threo isomer and CeCb was added to obtain the erythro adduct. This methodology was applied to the synthesis of ( )- and (Z)-isosafroles (232) and... 

Poly(dibenzosilole)s are a relatively new class of compounds for the area of organic electronic materials. Poly(dibenzosilole)s are not easily oxidised and have advantages of solubility and processibility over other polyfluorene analogues, such as carbazoles, dibenzophosphole oxides and dibenzothiophene dioxides. Several groups have already incorporated poly(dibenzosilole)s in the latest organic electronic devices such as OLEDs, OFETs and OSCs and have found improved performance over similar polyfluorene-based devices. With continual advancement in their synthesis, dibenzosilole-based polymers are set to match the popularity of polyfluorenes in organic electronic materials. 

A sterically hindered arylithium may react with POCI3 to give the diarylphosphinic chloride a specific example of one such synthesis is that of bis(2,4,6-triisopropylphenyl)phos-phinic chloride". Reactions 36" and 37" exemplify the use of monolithiated species. The use of 2,2 -dilithiobiphenyls leads to dibenzophospholes (239/ and the procedure has been extended to include the use of appropriately lithiated quaterphenyls". ... 

A new synthesis giving good yields of highly substituted phosphole oxides (24) is the reaction of aluminium halide complexes of cyclobutadienes (23) with phosphonous dichlorides (Scheme 2). The synthesis of several substituted dibenzophospholes, e.g., (25), has been reported. ... 

A series of papers describes the synthesis (and some reactions) of highly sterically hindered phosphinic acids based on the dibenzophosphole system, e.g., (36) and (37). These papers describe an improved synthesis of 5-phenyldibenzo-phosphole from tetraphenylphosphonium bromide, as well as that of 5-hydroxy-... 

Thoumazet C, Ricard L, Grutzmacher H, Le Floch P (2005) Dibenzo[a,d]cycloheptenyl dibenzophosphole palladium dichloride synthesis. X-ray-crystal structure and application in the Suzuki-Miyaura coupling. Chem Comm 1592... 

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