Intramolecular cyclisation of substituted phenoxyethanols and related compounds with mercury(II) oxide and iodine

Abstract

Electron-donating substituents have been shown to promote intramolecular cyclisation of 2-phenoxyethanols to form Ar₁-5 and Ar₂-6 cyclisation products. The meta-iodo-substituent promotes Ar₂-6 cyclisation to form 2,3-dihydro-1,4-benzodioxins. The Ar₂-6 cyclisation product from 3-phenylpropan-1-ols has been shown to be formed by rearrangement of an Ar₁-5 intermediate in which carbon migrates in preference to oxygen. Ar₁-6 cyclisation of 3-phenoxypropan-1-ols is shown to occur less readily than the corresponding Ar₁-5 cyclisation of 2-phenoxyethanols.