4-Allylphosphaisocoumarins can be prepared in good yield and with high regioselectivity by the reaction of o-ethynylphenylphosphonic acid monoesters with allyl bromide catalyzed by CuI. The present reaction represents the first example of a phosphonic acid monoester cyclized coupling reaction with alkyl halide.
phosphaisocoumarin - bioactivity -
o-ethynylphenylphosphonic acid monoester - cyclization - coupling