Diphenylphosphinoethane, palladium

For trisubstituted olefins, the nucleophile attacks predominantly at the less substituted end of the allyl moiety, e.g. to afford a 78 22 mixture of 13 and 14 (equation 7). Both the oxidative addition of palladium(O) and the subsequent nucleophilic attack occur with inversion of configuration to give the product of net retention7. The synthesis of the sex pheromone 15 of the Monarch butterfly has been accomplished by using bis[bis(l,2-diphenylphosphinoethane)]palladium as a catalyst as outlined in equation 87. A substitution of an allyl sulfone 16 by a stabilized carbon nucleophile, such as an alkynyl or vinyl system, proceeds regioselectively in the presence of a Lewis acid (equation 9)8. The... 

Burmeister has recently shown that this metathetical reaction is a convenient method for the preparation of some palladium(II) complexes which cannot be synthesized by direct reaction of the ligand with tetrachloropalladate(II) ion. By this method he has prepared dichloro(diphenylphosphinoethane)palladium (II), as well as complexes containing ligands other than those of the organophosphorus type, for example, dichlorobis(thiourea)-palladium(II), [PdChl (NH2)2CS 2], and dichlorobis(2,3,5,6-tetraphenylpyridine)palladium(II), [PdCh(C5NHPh4)2]."... 

Lactone synthesis.2 Carbonylation of simple organic halides can be carried out readily with several palladium catalysts such as bis(diphenylphosphinoethane)-his(triphenylphosphine)palladium(0) and dichlorobis(triphenylphosphinc)pal-ludium(ll). The latter catalyst is preferred because it is stable and easily converted to Pd(0) in situ. Carbonylation of halo alcohols provides a useful synthesis of various lactones. 

The benzamide bisdiene 134 proved to be a particularly good substrate for the carbocyclization with 1-pyrrolidino-l-cyclohexene. Its cyclization using 2 equiv of triph-enylphosphine or tris(o-tolyl)phosphine or 1 equiv of diphenylphosphinoethane (dppe) in conjunction with Pd(OAc)2 proceeds in about 90% overall yield to the substituted N-acylpyrrolidine 135 (Scheme 43). Notably, indole also proves to be an effective trapping reagent in the reaction of 134. The adduct 136 is obtained in 91% yield from the palladium acetate-catalyzed reaction in the presence of lris(( -tolyl)phosphine. 

PaUadium(n) enolate complex intermediates are also generated by the silicon-palladium exchange reaction of silyl enol ethers with 7r-allylpalladium(ll) alkoxide intermediate, which is formed in situ from aUyl carbonate with palladium-phosphine complex. With a catalytic amount of Pd(OAc)2 and dppe (diphenylphosphinoethane) in acetonitrile, silyl... 

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