Phosphines, multisite

Figure 3.40 Plenio s multisite phosphine ligand based on poly(methylstyrene).

In 2001, Engel and Gade [57] prepared a series of chiral phosphine-functionalized poly(propyleneimine) (PPI) dendrimers (29) by the reaction of carboxyl-linked C2-chiral pyrphos ligand (pyrphos, 3,4-bis(diphenylphosphino) pyrrolidine) with commercially available zero- to fourth-generation PPI. The subsequent metallation of multisite phosphines with [Rh(COD)2]-BF4 (COD, 1,5-cyclooctadiene) was in situ generated and carried out in the asymmetric hydrogenation of Z-methyl-a-acetamido cinnamate and dimethyl itaconate (Figure 4.28, Equation 1). In contrast... 

---