A simple and efficient method is proposed for the synthesis of tetrahydrobenzo[b]pyrans with aromatic aldehydes, active methylene compounds, and dimedone using basic ionic liquid catalyst in water. The procedure offers several advantages including short reaction time, good yield, easy procedure, and good recyclability of catalysts, which may be a practical alternative to conventional processes for preparation of 4-hpyrans.
In this paper, a simple and environment-friendly protocol was developed for the synthesis of arylsulfonyl 4H-pyrans via L-proline-catalyzed one-pot two-step reaction of aromatic aldehyde with phenylsulphonyl acetonitrile and dimedone under ball-milling conditions. Environmental acceptability, wide substrate scope, low cost and operational simplicity are the key features of this method.