Synthesis of Chiral α,β-Unsaturated γ‑Amino Esters via Pd-Catalyzed Asymmetric Allylic Amination

A Pd-catalyzed asymmetric allylic amination of 4-substituted 2-acetoxybut-3-enoates with amines has been developed for the regiospecific synthesis of chiral α,β-unsaturated γ-amino esters. The desired chiral aminated products can be obtained in up to 98% yield, and 99% ee and can be conveniently transformed to chiral γ-amino acid/alcohol derivatives and chiral γ-lactams, which can then be subjected to the synthesis of several types of chiral drugs and drug candidates. The preferential formation of chiral γ-amino esters may be attributed to the bulky substituents on the right side of the allyl substrates. This work provides an efficient strategy for the synthesis of chiral α,β-unsaturated γ-amino esters and their derivatives

Synthesis of Chiral α,β-Unsaturated γ‑Amino Esters via Pd-Catalyzed Asymmetric Allylic Amination

A Pd-catalyzed asymmetric allylic amination of 4-substituted 2-acetoxybut-3-enoates with amines has been developed for the regiospecific synthesis of chiral α,β-unsaturated γ-amino esters. The desired chiral aminated products can be obtained in up to 98% yield, and 99% ee and can be conveniently transformed to chiral γ-amino acid/alcohol derivatives and chiral γ-lactams, which can then be subjected to the synthesis of several types of chiral drugs and drug candidates. The preferential formation of chiral γ-amino esters may be attributed to the bulky substituents on the right side of the allyl substrates. This work provides an efficient strategy for the synthesis of chiral α,β-unsaturated γ-amino esters and their derivatives

The Construction of Chiral Fused Azabicycles Using a Pd-Catalyzed Allylic Substitution Cascade and Asymmetric Desymmetrization Strategy

A highly enantioselective Pd-catalyzed asymmetric allylic substitution cascade of cyclic <i>N</i>-sulfonylimines with an accompanying asymmetric desymmetrization has been developed for the construction of fused tetrahydroindole derivatives bearing two chiral centers. Mechanistic studies confirmed that the cascade reaction proceeds by initial allylic alkylation and subsequent allylic amination. The first alkylation is a chirality-control step and represents an asymmetric desymmetrization of <i>cis</i>-cyclic allyl diacetates. The reaction has been performed on a gram scale, and the desired products can take part in several transformations

Asymmetric Hydrogenation of α‑Substituted Acrylic Acids Catalyzed by a Ruthenocenyl Phosphino-oxazoline–Ruthenium Complex

Asymmetric hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX–Ru as a chiral catalyst under 5 bar H₂, affording the corresponding chiral α-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to construct bioactive chiral molecules. The asymmetric protocol was successfully applied to an asymmetric synthesis of dihydroartemisinic acid, a key intermediate required for the industrial synthesis of the antimalarial drug artemisinin