A Rh(II)-catalyzed formal [3+3] cyclization of diazonaphthoquinones and propargyl alcohol is reported to afford 2,3-dihydro-1,4-benzodioxins. Various terminal propargyl alcohols react with diazonapthoquinone in the presence of Rh₂(OAc)₄ to give the corresponding dihydrodioxins in good to high yields. However, dihydrodioxins are not formed in the reaction of internal propargyl alcohols, and the O–H insertion product and 2,5-dihydrofurans are formed as the main product(s) depending on the terminal substituent. 2,3-Dihydro-1,4-benzodioxins are proposed to be formed via Rh(II)-catalyzed intermolecular oxonium ylide formation and subsequent 6-exo-dig cyclization with the internal alkynyl group.

据报道，Rh（II）催化的重氮萘醌和炔丙醇的正式[3 + 3]环化反应可提供2,3-二氢-1,4-苯并二恶英。各种末端炔丙醇在Rh ₂（OAc）₄的存在下与重氮萘醌反应，以高至高收率得到相应的二氢二恶英。但是，在内部炔丙醇的反应中不会形成二氢二恶英，取决于末端取代基，OH插入产物和2,5-二氢呋喃是主要产物。提出通过Rh（II）催化的分子间氧鎓叶立德形成和随后的内部炔基6- exo - dig环化反应形成2,3-二氢-1,4-苯并二恶英。