ヨウ素環化反応を利用するベンゾフラン環の簡便構築法

抄録

In construction of 3-iodobenzo[b]furans by iodocyclization of 2-alkynylphenol derivatives, there are some problems that 2-alkynylphenol itself is unstable or hazardous halomethanes are generated in the reaction. Herein, we report an iodocyclization of ethoxyethylethers to alkynes for the synthesis of 3-iodobenzo[b]furans. The advantages of our method are: 1) ethoxyethylether serves not only as the protecting group but also as a directing group for the preparation of precursors for iodocyclization; 2) the synthesis requires a reasonable number of steps from starting material to 3-iodobenzo[b]furans; 3) the title compounds are afforded not only in short reaction but also in high yields without the generation of hazardous halomethanes; and 4) various 3-iodobenzo[b]furans can be obtained in good to excellent yields.