Design and evolution of copper apatite catalysts for N-arylation of heterocycles with chloro- and fluoroarenes.
We report the preparation of recyclable heterogeneous catalysts, copper-exchanged fluorapatite, and copper-exchanged tert-butoxyapatite by incorporating basic species F-/tBuO- in apatite in situ by coprecipitation and subsequent exchange with Cu(II). These basic copper catalysts catalyzed N-arylation of imidazoles and other heterocycles with chloroarenes and electron-poor fluoroarenes in good to excellent yields. Synthesis and characterization of some of the intermediates of the catalytic cycle gave some insight into the mechanism of the very important organic transformation. The necessity of basic sites for the activation of C-Cl and C-F bonds in the N-arylation of heterocycles with haloarenes is well-established.
Choudary
Boyapati M
BM
Inorganic Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India. bmchoudary@yahoo.com
Sridhar
Chidara
C
Kantam
Mannepalli L
ML
Venkanna
Gopaldasu T
GT
Sreedhar
Bojja
B