Synthesis of 5,6-dehydrokawain and some fluorinated analogues

An efficient methodology for the synthesis of 6-styrenylpyrone in a four-step sequence is reported. The reactions were performed under catalyst-free conditions with mild and affordable reagents to produce 5,6-dehydrokawain and fluorinated derivatives in good to excellent overall yields (72–86%) on a multigram scale. Two novel difluorinated derivatives are reported here for the first time.