Direct Preparation of 3‑Iodochromenes from 3‑Aryl- and 3‑Alkyl-2-propyn-1-ols with Diaryliodonium Salts and NIS

On
the basis of a study of the O-phenylation of
3-phenyl-2-propyn-1-ol with diphenyliodonium triflate and t-BuONa, a variety of 4-aryl-3-iodo-2H-benzopyrans
were prepared in good to moderate yields in one pot from the reaction
of 3-aryl-2-propyn-1-ols with diaryliodonium triflates and t-BuONa, followed by the treatment with N-iodosuccinimide and BF3·OEt2, under transition-metal-free
and mild conditions. The formed 4-phenyl-3-iodo-2H-benzopyran was converted into 4-phenyl-2H-benzopyran
derivatives through C–C bond formations at the 3-position by
Pd-catalyzed coupling reactions and into coumarin with oxidants.