Department of Chemistry, National Central University, No. 300 Jhong-Da Road, Jhong-li, Taoyuan, 32001, Taiwan.
Org Biomol Chem. 2021 Dec 8;19(47):10390-10402. doi: 10.1039/d1ob01941d.
Bromotrimethylsilane (TMSBr)-promoted intramolecular cyclization of (-arylethynyl)benzyl ethers to form 1-isochromenes at room temperature is reported. Further studies indicated that vinyl carbocations are the reaction intermediates which are stabilized by the conjugated aryl groups. Thus, -addition of benzyl ethers/tetrahydropyrans to alkynes was achieved under metal-free, acidic conditions. These reaction conditions were compatible with an alkynyl Prins reaction; therefore, 1-isochromenes were produced directly from alkynyl benzaldehydes and alkynyl alcohols using a one-pot procedure.
报道了在室温下，三甲基溴硅烷（TMSBr）促进（-芳基乙炔基）苄基醚的分子内环化，形成 1-异色烯。进一步的研究表明，乙烯基碳正离子是反应中间体，芳基基团的共轭稳定了它们。因此，在无金属、酸性条件下，实现了苯醚/四氢吡喃与炔烃的 -加成。这些反应条件与炔基 Prins 反应相容；因此，直接通过一锅法，由炔基苯甲醛和炔基醇得到 1-异色烯。
