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

A series of easy-to-prepare and modular chiral ,-bidentate phosphoramidites were synthesized. With respect to Pd(II), these ligands showed the ability to form stable ,-chelate allylic complexes. The structures of the ligands and their complexes were confirmed by 2D NMR spectroscopy and single-crystal X-ray diffraction.

Diamidophosphites from β-hydroxyamides: readily assembled ligands for Pd-catalyzed asymmetric allylic substitution.

Two groups of modular chiral diamidophosphite ligands were easily synthesised from accessible N-Boc-amino alcohols and pseudodipeptides. The reaction of these compounds with [Pd(allyl)Cl] in the presence of AgBF yielded complexes [Pd(allyl)(L)]BF. In addition, metallochelates [Pd(allyl)(L)]BF with (S)-methioninol-based P,S-bidentate ligands were prepared.

Base mediated 1,3-dipolar cycloaddition of α-substituted vinyl phosphonates with diazo compounds for synthesis of 3-pyrazolylphosphonates and 5-pyrazolcarboxylates.

5-Aryl-substituted pyrazol-3-ylphosphonates have been conveniently synthesized by 1,3-dipolar cycloaddition of 1-formamidovinylphosphonates and aryldiazomethanes under KCO/MeOH conditions at room temperature. These pyrazoles are formed in one pot via spontaneous elimination of formamide. Basic conditions prevent competitive formation of cyclopropylphosphonates.