Work

Cinchona Alkaloid‐Catalyzed Enantioselective Amination of α,β‐Unsaturated Ketones: An Asymmetric Approach to Δ2‐Pyrazolines

Year: 2011

Type: article

Abstract: Δ2‐Pyrazolines are of significant medicinal and synthetic interest due to their therapeutic properties and utility in the synthesis of 1,3‐diamines, yet few asymmetric methods exist to prepare them. An unprecedented and highly enantioselective organocatalytic synthesis of 2‐pyrazolines was achieved through an asymmetric conjugate addition catalyzed by 9‐epi‐amino Cinchona alkaloids followed by deprotection‐cyclization, which furnished chiral 2‐pyrazolines in 46–78% yield and 59–91% ee. This bifunctional catalytic methodology thus provides easy access to a considerable range of optically active 3,5‐dialkyl 2‐pyrazolines.

Source: Advanced Synthesis & Catalysis

DOI: 10.1002/adsc.201100447

Authors: Nathaniel R. Campbell, Bingfeng Sun, Ravi P. Singh, Li Deng

Institution: Brandeis University

Language: English

Topic: Asymmetric Synthesis and Catalysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Institutes of Health, National Institute of General Medical Sciences

Award: Catalytic Umpolung Reactions of Imines