Synthesis of Isocoumarins and α-Pyrones via Palladium-Catalyzed Annulation of Internal Alkynes
作者:Richard C. Larock、Mark J. Doty、Xiaojun Han
DOI:10.1021/jo9821628
日期:1999.11.1
factors. A number of 3,4-disubstituted isocoumarins and polysubstituted alpha-pyrones have been prepared in good yields by treating halogen- or triflate-containing aromatic and alpha,beta-unsaturated esters, respectively, with internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides an especially simple and convenient regioselective route to isocoumarins and alpha-pyrones
通过在钯催化剂的存在下用内部炔烃分别处理含卤素或三氟甲磺酸酯的芳族和α,β-不饱和酯,已经以良好的产率制备了许多3,4-二取代的异香豆素和多取代的α-吡喃酮。合成地,该方法提供了一种特别简单和方便的区域选择性途径,用于对含有芳基,甲硅烷基,酯,叔烷基和其他受阻基团的异香豆素和α-吡喃酮。据信该反应通过七元的Paladacyclic环复合物进行,其中反应的区域化学由空间因素控制。通过分别处理含卤素或三氟甲磺酸酯的芳族和α,β-不饱和酯,已经以高收率制备了许多3,4-二取代的异香豆素和多取代的α-吡喃酮,在钯催化剂存在下与内部炔烃反应。综上,该方法为包含芳基,甲硅烷基,酯,叔烷基和其他受阻基团的异香豆素和α-吡喃酮提供了特别简单和方便的区域选择性途径。据信该反应通过七元的Paladacyclic环复合物进行,其中反应的区域化学由空间因素控制。