TADDOL-based ,-bidentate phosphoramidite ligands in palladium-catalyzed asymmetric allylic substitution

• Published in: Organic & biomolecular chemistry 2024-01, Vol.22 (3), p.538-549
• Main Authors: Gavrilov, Konstantin N, Chuchelkin, Ilya V, Firsin, Ilya D, Trunina, Valeria M, Gavrilov, Vladislav K, Zheglov, Sergey V, Fedorov, Denis A, Tafeenko, Victor A, Zamilatskov, Ilya A, Zimarev, Vladislav S, Goulioukina, Nataliya S
• Format: Article
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/d3ob01891a

A series of easy-to-prepare and modular chiral P , S -bidentate phosphoramidites were synthesized. With respect to Pd( ii ), these ligands showed the ability to form stable P , S -chelate allylic complexes. The structures of the ligands and their complexes were confirmed by 2D NMR spectroscopy and single-crystal X-ray diffraction. These chiral inducers provided up to 99% ee in the Pd-catalyzed asymmetric allylic substitution of ( E )-1,3-diphenylallyl acetate with C- and N-nucleophiles and up to 94% ee in the Pd-mediated allylic alkylation of cinnamyl esters with β-ketoesters and 2,5-dimethylpyrrole. Furthermore, up to 92% ee with quantitative conversion and chemo- and regioselectivity was achieved in the rare reaction between 2-(diethoxyphosphoryl)-1-phenylallyl acetate and aniline. The effects of the structural parameters, reaction conditions and ligand-to-metal ratio on the catalytic results are discussed. It was shown that the ligands surpass their analogues with different denticity. Phosphoramidite-thioethers with a TADDOL backbone as brand new P , S -bidentate stereoselectors for Pd-mediated asymmetric allylation.