First I2-K2CO3-promoted sequential C-N and C-O bond forming approach for one-pot synthesis of 1,4-benzoxazines

I-2-K2CO3 combination has been found to be an efficient, reusable, and inexpensive catalyst system for the one-pot synthesis of 3-aryl-2H-benz[1,4]oxazine via rapid C=N and C-O bond formation. No by-product formation, operational simplicity, ambient temperature, and high yield (85-94%) are the attractive features of the envisaged reaction. The reported one-pot synthesis of 1,4-benzoxazine involves the application of I-2-K2CO3 catalyst system for the first time and proceeds via in situ imine formation followed by intramolecular ring transformation cascades. (C) 2013 Elsevier Ltd. All rights reserved.