Intramolecular Alkene Aminopalladation Reactions of (dppf)Pd(Ar)[N(Ar¹)(CH₂)₃CH═CH₂] Complexes. Insertion of Unactivated Alkenes into Pd−N Bonds

Abstract

The synthesis of (dppf)Pd(C(6)H(4)-p-F)[N(Ar(1))(CH(2))(3)CH horizontal lineCH(2)] complexes (3), which are thought to be intermediates in Pd-catalyzed alkene carboamination reactions, is described. These complexes undergo syn-migratory insertion of the alkene into the Pd-N bond to yield observable (dppf)palladium(aryl)(pyrrolidin-2-yl-methyl) complexes 6. Reductive elimination from 6 provides 2-benzylpyrrolidine derivatives 4. The rates of conversion of 3 to 6 (k(1)) and 6 to 4 (k(2)) were measured and are within 1 order of magnitude of each other. The syn-migratory insertion stereochemistry was confirmed through a deuterium labeling experiment. These are the first examples of syn-migratory insertions of unactivated alkenes into Pd-N bonds of well-defined complexes.