Ferrocenes PPFA ligands

The use of ferrocene-based ligands such as 3 and PPFA (8) result in the formation of catalysts that extended the scope of the arylation reaction to more difficult transformations [37,38,56]. For example, di-n-butylamine could now be effectively coupled with electronically neutral as well as electron-deficient aryl bromides. Reaction of 4-ferf-butylbromobenzene with di-n-butylamine with the ( )-BlNAP/Pd- or DPPF/Pd-based catalysts resulted in significant amounts of terf-butylbenzene formation, however the use of ligands 3 and 8 resulted in formation of the desired product in excellent yield, Eq. (25). 

The chiral phosphines used are shown in Figure 1 and representative results are summarized in Table I. Among the ferro-cenylphosphines, (5)-(/ )-PPFA was one of the most effective ligands giving the coupling product, 3-pheny1-1-butene (3a), in up to 68% ee in the reaction of la with 2a. The ferrocene planar... 

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