Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
Sunita K. Gadakh, Soumen Dey and Arumugam Sudalai*
*Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra, India-411008, Email: a.sudalaincl.res.in
S. K. Gadakh, S. Dey, A. Sudalai, J. Org. Chem., 2015, 80, 11544-11550.
DOI: 10.1021/acs.joc.5b01713 (free Supporting Information)
An efficient annulation of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent provides high yield of coumarin derivatives via C-H bond activation. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity.
see article for more examples