Allylic derivatives migratory insertion

Inversion of configuration observed with allyl and benzyl derivatives has been deduced from the results sununarized in Scheme 4. In the case of allyl derivatives, a very reasonable and seemingly unmistakable assumption that nucleophilic attack on 7r-allyl ligands takes place on the side opposite to Pd was made. On the other hand, an equally plausible assumption that migratory CO insertion and methanolysis of acylpalladium derivatives both proceed with retention. ... 

VL3 Migratory Insertion Reactions of Allyl, Propargyl, and Allenylpalladium Derivatives Involving Carbon Monoxide and Related Derivatives... 

Further examples of such migratory insertion processes were subsequently studied computationally. Kirchner showed that the formation of a stable allyl-alkylidene 13 derived from the metalacyclopentatriene species 12 via intramolecular attack of the NHC ligand (Scheme 2.5). The migratory insertion of an alkyne into a NHC-Ru bond was also suggested to account for the formation of This reaction, for which there was no precedent in... 

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