Synthesis of 2,2-dimethylchromens

Abstract

a,a-Dimethylpropargyl ethers of simple phenols are readily prepared in high yields. Thermal rearrangement of them affords 2,2- dimethylchromens, also in high yields. These reactions are used to prepare the natural products, ageratochromen, evodionol methyl ether, lapachenole, seselin, luvangetin, and braylin.     A base-catalysed Wessely-Moser rearrangement is reported.