A newly developed π-allylpalladium with a (-)-β-pinene framework and an isobutyl side chain catalyzed the enantioselective allylation of imines in good yields and enantioselectivities (20 examples, up to 98% ee). An efficient enantioselective synthesis of the (R)-α-propyl piperonylamine part of DMP 777, a human leukocyte elastase inhibitor and (R)-pipecolic acid have been achieved as a useful application of this methodology.

This review highlights the palladium-catalyzed allylic C–H functionalizations via π-allyl palladium reported from early 2014 to present date.

The cascade aza‐Cope/aza‐Prins cyclization of homoallylamines to give substituted piperidines has been explored. The use of glyoxalic acid as the carbonyl component afforded bicyclic structures as a result of the internal carboxylate anion trapping the intermediate cation. The unimolecular bis‐, tris‐, and tetrakis(homoallylamine)s efficiently delivered the appended bis‐, tris‐ and tetrakis(piperidine‐4‐ol)s (tripod and crucifix shape, respectively) as new entities. The latter compound served as an excellent ligand in the Suzuki–Miyaura cross‐coupling reaction to synthesize incrustoporin.

An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C-H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen's gland lactone analogues via intramolecular iodoetherification.

A collective synthesis of a γ-butyrolactone class of paraconic acids such as (+)-methylenolactocin, (+)-phaseolinic acid, (+)-nephrosteranic acid, (+)-nephrosterinic acid, (+)-rocellaric acid and (+)-protolichesterinic acid is described. The strategy adopted is protecting-group-free based on efficient Pd-catalyzed Suzuki-Miyaura coupling and Ru-catalyzed Sharpless oxidation to construct the core β-COH-γ-butyrolactone unit to accomplish the synthesis of various paraconic acids.