Catalytic Asymmetric Allylic Amination with Isatins, Sulfonamides, Imides, Amines, and <i>N</i>-Heterocycles
作者:Ciarán C. Lynch、Kaluvu Balaraman、Christian Wolf
DOI:10.1021/acs.orglett.0c00936
日期:2020.4.17
A generally useful palladium-catalyzed method for the asymmetricallylicamination with a large variety of isatins, sulfonamides, imides, amines, and N-heterocycles is introduced. A single protocol with a readily available catalyst accomplishes this reaction at room temperature with high yields and enantioselectivities often exceeding 90%, which is demonstrated with 31 examples.
Synthesis of chiral fluorine-containing compounds via Pd-catalyzed asymmetrical allylations of dimethyl 2-fluoromalonate using sulfonamide-pyridine ligands
Chiral o-aniline sulfoxides serving as chiral sulfurous source were synthesized, from which new sulfonamide-pyridine ligands were made in three-steps. These compounds proved to be efficient S,N-ligands for enantiocontrol of palladium-catalyzed allylic substitutions of dimethyl 2-fluoromalonate. The induced effect of the Pd/S,N-ligand catalyst on the enantioselectivity depends on the steric demand of
A new class of highly stable O,N,N,O-tetradentate bioxazolineligands were synthesized from l-tartaric acid. Exploration of those ligands in Pd-catalyzed asymmetric allylic alkylation yielded alkylated product up to 96% ee. Necessity of additional chelation to obtain high enantioselectivity was also demonstrated. Structural modifications of this ligand might result in identification of a novel privileged
Tartrate-derivedbioxazolineligands, which form a five-membered chelate ring with metals, were evaluated for use in the asymmetric allylic alkylation (AAA) reactions of various symmetrical and unsymmetrical allylacetates. Excellent enantioselectivities were achieved by using both symmetrical and unsymmetrical allylacetates.
Synthesis and application of a new hexamethyl-1,1′-spirobiindane-based chiral bisphosphine (HMSI-PHOS) ligand in asymmetric allylic alkylation
作者:Shirui Chang、Lei Wang、Xufeng Lin
DOI:10.1039/c8ob00279g
日期:——
The emerging and versatile application of chiral bisphosphine ligands in diverse asymmetricreactions has resulted in great demand for novel bisphosphine ligands containing different innovative backbones. Herein, a new type of chiral spiro bisphosphine ligand (HMSI-PHOS) has been developed on the basis of a hexamethyl-1,1′-spirobiindane motif. A series of new HMSI-PHOS ligands were synthesized and