Nature of the interaction between β-substituents and the allyl moiety in (η3-allyl)palladium complexes

Substrate‐Controlled Palladium‐Catalyzed Allylic Alkylations of Chelated Enolates – Scope and Limitations

“…[17a] This is in good agreement with calculations carried out by Szabó et al [22] These indicate that electron-withdrawing substituents adjacent to the p-allyl-palladium complex are oriented more or less antiperiplanar to the palladium, and that the nucleophilic attack occurs at the allylic position away from the heteroatom.…”

(η3-Phenylallyl)(phosphanyloxazoline)palladium Complexes: X-Ray Crystallographic Studies, NMR Investigations, and Ab Initio/DFT Calculations (Phosphanyloxazoline)palladium Complexes, Part II. Part I see: ref. 5.

“…[9]) and excellent results have been achieved on the aspects of isomer distributions [5,23] and substitution reactions (transition-state structure, [24] regioselectivity, and [25] electronic substituent effects [26] ). Complex 1, displaying as four different isomers in solution and in addition providing X-ray crystal data, was the most interesting target for quantum-chemical calculations.…”

Regio‐ and Stereocontrolled Palladium‐Catalyzed Allylic Substitution on N‐Acetylneuraminic Acid Derivatives

“…Both sterics and electronics play a role in determining the outcome of the reaction, and the regiochemistry of the nucleophilic attack can be affected by, among other factors, the nucleophile, [2] the nature of the ligand associated with the allylpalladium complex, [3] or the substituents in the substrate. [4] In our ongoing involvement in the synthesis of new sialic acid constructs [5] we have been interested in their preparation through Pd 0 -catalyzed allylic substitution of 2,3-unsaturated N-acetylneuraminic acids. [6] Indeed, the development of efficient synthetic methods for the preparation of N-acetylneuraminic acid (Neu5Ac) conjugates and modified structures for biological research has been a major focus in carbohydrate chemistry, due to their central role in physiological processes and diseases.…”