Phosphines trans-chelating

The trap (trans-chelating phosphines) ligands developed by Ito and co-workers [33] form nine-membered metallocycles where trans-chelation is possible. However, it is not clear whether the cis isomer which has been shown to be present in small amounts or the major trans isomer is responsible for the catalytic activ-... 

High n/b ratios (3.7-13) are obtained in the platinum-catalyzed hydrofbrmylation reaction n/b ratios as high as 99 have been obtained utilizing a chelating phosphine, trans-1,2-diphenylphosphinocyclo-butane.10... 

With long chain bis(phosphines) (n = 4 - 16), trans chelate rings become possible, although with the longest chains bridged dinuclear species would be expected. 

A chiral bisphosphine containing two ferrocene molecules has been prepared using Ugi s lithiation as a key step (Scheme 2-9) [20], Thus, the diphenylphosphinyl group is introduced at the ferrocenylmethyl position of the iodide obtained from lithiated ferrocene 2. Oxidative coupling of the iodoferrocene followed by reduction of the phosphine oxide gives the bisferrocene-bisphosphine 15. The bisphosphine is unique in that a trans-chelate is formed on its coordination to a metal. 

Both of the most famous tran -chelating phosphines, BISBI [12] and the similar 2,2 -bis(diphenylphosphinomethyl)-l-T-binaphthalene [13], can be sulfonated ... 

The cyclometallated palladium and platinum derivatives of trimesityl phosphine or arsine react with pyrazole or 3,5-dimethylpyrazole to form metal chelates 243 (E = P, As M = Pd, Pt R = H, Me) having the trans configuration (81TMC24). 

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