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The preparation of a new class of "roofed" β-iminodisulfides from sterically congested, conformationally rigid chiral 2-thiazolidinones is described. A functional survey of palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate proved that symmetrical "roofed" β-iminodisulfides are efficient chiral ligands, showing enantioselectivity opposite that associated with chiral "roofed" β-iminothioether ligands.

N‐heterocyclic olefin (NHO) is known as a highly electron‐donative ligand, but its application to metal catalysts has rarely been studied. In this study, we synthesized 2‐methyleneimidazolidine ligands equipped with a bicyclic frameworks with the goal of developing a NHO‐ligated Pd catalyst. These synthesized [(NHO)PdCl(μ‐Cl)]2 complexes had a phosphine co‐ligand that proved effective as a catalyst for Suzuki‐Miyaura coupling at ambient temperature. By optimizing the N‐substituents of NHO ligands and a phosphine co‐ligand, we developed a [(NHO)Pd{[2‐(CH3O)C6H4]3P}Cl2] complex as a catalyst that shows good catalytic activity. [ABSTRACT FROM AUTHOR]

A method for the synthesis of imidazolinium salts through a catalytic dehydrogenation was developed using Pd/C as a catalyst with ammonium salt as an additive. Optimization of the reaction conditions revealed the existence of a proton source that was necessary to accomplish the reaction. Under the optimal conditions, oxidation‐sensitive components, such as an allyl, a furan, and a thiophene can be introduced into the corresponding imidazolinium salts. In addition to the varied N‐substituents, the presented method can be used to synthesize a series of 2‐substituted imidazolinium salts. [ABSTRACT FROM AUTHOR]