Abstract
Lewis acid ZnCl2 promoted cyclization protocol to 4H-chromenes is accomplished, using readily available phenols and acetophenones as starting materials. Interestingly, the process is feasible under the solvent free environment. Synthesis of a variety of 4H-chromenes have been accomplished using this strategy. In addition, this concept is extended to the synthesis of ortho-benzylphenols by treating phenols either with styrenes or secondary benzylic alcohols.
Graphical Abstract
Acknowledgment
We are very much thankful to the Council of Scientific and Industrial Research [(CSIR), No. 02(0262)/16/EMR-II], New Delhi, for financial support and C.B.S. thank UGC for the award of a research fellowship.