Large bite angle diphosphines

Stereoselectivity in hydroformylation reactions, as a result of the supporting ligand set (e.g. large bite angle diphosphines or chiral diphosphines) or by stereocontrol of the substrate has also been discussed by Breit. Rhodium complexes supported by large bite angle diphosphines such as bisbi, biphephos and xantphos, shown in Scheme 10, are now well-established... 

Dudle B, Rajesh K, Blacque O, Berke H (2011) Rhcaiium nitrosyl complexes bearing large-bite-angle diphosphines. Organometallics 30 2986-2992... 

Another approach to large-bite-angle diphosphines was claimed by BASF [57]. First, l,2-bis(ort/zo-chlorophenyl)-substituted cyclic five- or six-membered backbones were constructed, which were eventually decorated with diphenylphosphino groups (Scheme 2.19). 

Scheme 2.19 Large-bite-angle diphosphines with a cydopentane backbone. 2.1.3...

Figure 5.3 Large-bite-angle diphosphines suitable for isomerization-hydroformylation.

A water-soluble diphosphine ligand with large bite angle was prepared by controlled sulfonation of XANTHPHOS. The rhodium complex of the resulting (2,7-bis(S03Na)-XANTHPHOS (51) showed a catalytic activity in propene hydroformylation comparable to Rh/TPPTS (TOF 310 vs 500 h" at 120 °C, 9 bar propene and 10 bar CO/H2 = 1/1) [70]. The regioselectivity... 

Diphosphines with large bite angles are useful ligands to diminish the extent of P-hydrogen elimination. As a notable example, PdQjldppf) is a competent catalyst for the alkylation of both alkenyl triflates [157] and phosphates [158]. 

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