Bis-allylpalladium species

Nickel(O) complexes are extremely effective for the dimerization and oligomerization of conjugated dienes [8,9]. Two molecules of 1,3-butadiene readily undergo oxidative cyclization with a Ni(0) metal to form bis-allylnickel species. Palladium(O) complexes also form bis-allylpalladium species of structural similarity (Scheme 2). The bis-allylpalladium complexes show amphiphilic reactivity and serve as an allyl cation equivalent in the presence of appropriate nucleophiles, and also serve as an allyl anion equivalent in the presence of appropriate electrophiles. Characteristically, the bis-allylnickel species is known to date only as a nucleophile toward carbonyl compounds (Eq. 1) [10,11],... 

In the recent development of a one-pot borylation of allylic acetates (e.g., 37) followed by in situ addition to sidfonyl-imines, Szabo and co-workers observed that the palladium catalyst is required for the addition of the transient allylboronate 38 to the N-sulfonyl imine (Equation 46) [59]. The authors proposed the intermediacy of a bis-allylpalladium species to explain this result. These additions are highly regio- and stereoselective. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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