BPPFA-palladium

Palladium(0)-catalyzed kinetic resolution of racemic ally acetate 15 which gives rise to unsym-metrically 1,3-disubstituted zr-allyl complexes has been attempted using 0.5 equivalents of sodium azide in the presence of ferrocenylphosphine (R,pS)-BPPFA (B)40. The optical purities of both the resulting ally azide (.S )-16 and the unreacted starting material (A)-15 are close to zero. 

Optically active ferrocenylbisphosphines, (/J)-N,iV-dimethyl-l-[(5)-1, 2-bis(diphenylphosphino)ferrocenyIJethylamine [(/J)-(5)-BPPFA] and its derivatives, are efficient chiral bisphos-phine ligands for rhodium-catalyzed asymmetric hydrogenation, palladium-catalyzed asymmetric allylic substitution reactions, and gold-catalyzed asymmetric aldol-type reactions of a-isocyano carboxylates. ... 

The palladium-catalyzed coupling of silyl ketene acetals with aryl bromides in the presence of TlOAc has been applied to the asymmetric synthesis of 2-aryl-propionic acids (40—50% ee) by the use of BPPFA and several other chiral phosphine ligands (Scheme 2-16) [35]. 

E-1,4-bis(trimethylstannyl)-1,3-butadiene 174 bis(triphenylphosphane) palladium(O) 100 bombykol 64, 65 a-bond metathesis 37 9-borabicyclo[3.3.1]nonane 49 boron-zinc exchange 389, 396 (5)-(/ )-BPPFA 29 Bredt s rule 243 bromide-zinc exchange 404 1,4-bromoacetoxylation 366 1 -bromo-1 -alkenes 63 bromoboration of acetylene 51... 

It was found that the ferrocenylphosphines containing an (dialkylami-no)alkyl group on the side chain are effective for the cross-coupling of 2a catalyzed by nickel or palladium complexes [8, 9,10]. Ferrocenylmonophosphine, (S)-(iI)-PPFA (10a) and -bisphosphine, (S)-(i )-BPPFA (14) gave the coupling product 6 with 68% ee and 65% ee, respectively. The presence of the (dialkylami-no)alkyl side chain is of primary importance for the high selectivity and the enan-... 

The influence of the extent of conversion on enantioselectivity has been studied in the reaction of the Grignard reagent 2b with 4a catalyzed by the nickel complex of (S)-(1 )-BPPFA (14) [12]. A ferrocenylphosphine 16 which is analogous to PPFA but has a tetrahydroindenyl moiety was more enantioselective than PPFA (10a) for the palladium-catalyzed asymmetric cross-couphng of 2a with 4b to give (R)-6 of 79% ee [13] (entry 15). 

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