Amine-Catalyzed Asymmetric (3+3) Annulations of beta '-Acetoxy Allenoates: Enantioselective Synthesis of 4H-Pyrans

作者：Ni, Chunjie; Tong, Xiaofeng^*

来源：Journal of the American Chemical Society, 2016, 138(25): 7872-7875.

DOI：10.1021/jacs.6b04935

• CINCHONA ALKALOIDS
• PHOSPHINE CATALYSIS
• 4+2 CYCLOADDITION
• ALPHA,BETA-UNSATURATED KETONES
• COOPERATIVE CATALYSIS
• CHIRAL PHOSPHINES
• NATURAL-PRODUCTS
• ALLENIC ESTERS
• ORGANOCATALYSTS
• DIHYDROPYRANS

The asymmetric (3 + 3) annulations of beta'-acetoxy allenoates with either 3-oxo-nitriles or pyrazolones have been realized by using 6'-deoxy-6'-[(L)-N,N-(2,2'-oxidiethyl)-valine amido]quinine (6h) as the catalyst. The three functions of catalyst 6h, including Lewis base (quinuclidine N), H-bond donor (amide NH), and Bronsted base (morpholine N), cooperatively take crucial roles on the chemo- and enantioselectivity, allowing for the construction of 4H-pyran and 4H-pyrano[2,3-c]pyrazole in high yields and enantioselectivity.

• 出版日期2016-6-29
• 单位常州大学