Al(OTf)3-Catalyzed Preparation of 4-Hydroxy-3-propargylic Coumarins and Subsequent Regioselective Cyclization towards Furo- or Pyrano[3,2-c]coumarins
摘要:
An efficient and economical approach to functionalized furo[3,2-c]coumarin and pyrano[3,2-c]coumarin derivatives has been developed from 4-hydroxy-3-(prop-2-ynyl)coumarin derivatives through organocatalysis or metallo-organocatalysis. Selective 5-exo-dig' or 6-endo-dig' cyclization of the 4-hydroxy-3-(prop-2-ynyl)coumarin substrates could be achieved under organocatalytic {1,8-diazabicyclo[5.4.0]undec-7-ene} or metallo-organocatalytic (N-methylmorpholine/CuBr) conditions, respectively, to yield potentially bioactive heterocycles in excellent yields.
Al(OTf)3-Catalyzed Preparation of 4-Hydroxy-3-propargylic Coumarins and Subsequent Regioselective Cyclization towards Furo- or Pyrano[3,2-c]coumarins
摘要:
An efficient and economical approach to functionalized furo[3,2-c]coumarin and pyrano[3,2-c]coumarin derivatives has been developed from 4-hydroxy-3-(prop-2-ynyl)coumarin derivatives through organocatalysis or metallo-organocatalysis. Selective 5-exo-dig' or 6-endo-dig' cyclization of the 4-hydroxy-3-(prop-2-ynyl)coumarin substrates could be achieved under organocatalytic {1,8-diazabicyclo[5.4.0]undec-7-ene} or metallo-organocatalytic (N-methylmorpholine/CuBr) conditions, respectively, to yield potentially bioactive heterocycles in excellent yields.
of active natural products and pharmaceutically relevant molecules have received increasing attention. However, developing an adjustable system for selectively synthesizing them is still a challenging task. Herein, sulfonic acid-functionalized ionicliquid was successfully used as the catalyst for the alkylation of 4-hydroxycoumarin derivatives with secondary aromatic propargylic alcoholsusing dimethyl
Al(OTf)3-Catalyzed Preparation of 4-Hydroxy-3-propargylic Coumarins and Subsequent Regioselective Cyclization towards Furo- or Pyrano[3,2-c]coumarins
作者:Barend Bezuidenhoudt、Sudipta Ponra、Mukut Gohain、Johannes van Tonder
DOI:10.1055/s-0034-1379971
日期:——
An efficient and economical approach to functionalized furo[3,2-c]coumarin and pyrano[3,2-c]coumarin derivatives has been developed from 4-hydroxy-3-(prop-2-ynyl)coumarin derivatives through organocatalysis or metallo-organocatalysis. Selective 5-exo-dig' or 6-endo-dig' cyclization of the 4-hydroxy-3-(prop-2-ynyl)coumarin substrates could be achieved under organocatalytic 1,8-diazabicyclo[5.4.0]undec-7-ene} or metallo-organocatalytic (N-methylmorpholine/CuBr) conditions, respectively, to yield potentially bioactive heterocycles in excellent yields.