Chiral N-Heterocyclic Carbene Ligands Bearing a Pyridine Moiety for the Copper-Catalyzed Alkylation of<i>N</i>-Sulfonylimines with Dialkylzinc Reagents
Amino acid‐derived chiral imidazolium salts, each bearing a pyridine ring, were developed as N‐heterocyclic carbeneligands. The copper‐catalyzed asymmetric alkylation of various N‐sulfonylimines with dialkylzincreagents in the presence of these chiral imidazolium salts afforded the corresponding alkylated products with high enantioselectivity (up to 99 % ee). The addition of HMPA to the reaction
Rhodium-Catalyzed Enantioselective Arylation of Aliphatic Imines
作者:Naoya Kato、Tomohiko Shirai、Yasunori Yamamoto
DOI:10.1002/chem.201601246
日期:2016.6.1
Chiral rhodium(I)‐catalyzed highly enantioselective arylation of aliphatic N‐sulfonyl aldimines with arylboronic acids has been developed. This transformation is achieved by the use of a rhodium/bis(phosphoramidite) catalyst to give enantiomerically enriched α‐branched amines (up to 99 % ee). In addition, this system enables efficient synthesis of (+)‐NPS R‐568 and Cinacalcet which are calcimimetic
amidophosphine ligand 5 bearing two bulky substituents, 2,4,6-trimethylphenylmethyl or 2,4,6-triisopropylphenylmethyl groups, on the pyrrolidine ring was improved by employing the borane-THF reduction of the lactam-alcohol intermediate 8. The resulting amino alcohol was selectively acylated to give an amide-alcohol 11, which was then converted to the chloride 12 in 55-73% yields by the treatment with
Highly Enantioselective Arylation of <i>N</i>-Tosylalkylaldimines Catalyzed by Rhodium-Diene Complexes
作者:Zhe Cui、Hong-Jie Yu、Rui-Feng Yang、Wen-Yun Gao、Chen-Guo Feng、Guo-Qiang Lin
DOI:10.1021/ja2046217
日期:2011.8.17
A highly enantioselective rhodium-catalyzed arylation of aliphatic N-tosylaldimines has been developed. The combination of chiral bicyclo[3.3.0]octadiene ligands, an active rhodium hydroxide complex, and neutral reaction conditions is the key to achieving high yield and enantioselectivity. The application of this method is demonstrated by the enantioselective synthesis of chiral 2-aryl pyrrolidines