▁mod ular ▁and ▁it ▁is ▁not ▁normally ▁necessary ▁to ▁introduce ▁the ▁ph osph ine ▁and ▁ox az oline ▁mo iet ies ▁in ▁any ▁particular ▁order . ▁However ▁while ▁examples ▁exist ▁of ▁the ▁ph osph ine ▁being ▁introduced ▁first , ▁it ▁is ▁more ▁common ▁to ▁see ▁the ▁synth esis ▁of ▁a ▁ph eny lo x az oline ▁which ▁is ▁subsequently ▁combined ▁with ▁a ▁source ▁of ▁di phen yl ph osph ine . ▁Method s ▁for ▁doing ▁this ▁depend ▁on ▁the ▁nature ▁of ▁the ▁subs itu ent ▁in ▁the ▁X ▁position : ▁▁ ▁When ▁X ▁= ▁flu or ine ▁coupling ▁involves ▁an ionic ▁disp lacement ▁with ▁a ▁di phen yl ph osph ine ▁an ion ▁ ▁When ▁X ▁= ▁b rom ine ▁this ▁can ▁be ▁converted ▁into ▁a ▁Gr ign ard ▁re agent ▁and ▁react ed ▁with ▁ch lor odi phen yl ph osph ine , ▁or ▁couple d ▁with ▁di phen yl ph osph ine ▁via ▁a ▁co pper ▁i od ide ▁catal ys ed ▁reaction . ▁ ▁When ▁X ▁= ▁hydro gen ▁this ▁under go es ▁directed ▁orth o ▁l ith iation ▁( fac il itated ▁by ▁intr am ole cular ▁coord ination ▁with ▁the ▁ox az oline ) ▁followed ▁by ▁reaction ▁with ▁ch lor odi phen yl ph osph ine ▁ ▁Of ▁these ▁methods ▁the ▁co pper ▁i od ide ▁catal ys ed ▁reaction ▁method ▁is ▁by ▁far ▁the ▁simplest ▁to ▁carry ▁out , ▁as ▁it ▁does ▁not ▁require ▁the ▁synth esis ▁of ▁discrete ▁an ionic ▁or ▁organ omet all ic ▁species