A general and highly regio and stereoselective method for the synthesis of (E)-2-(2-arylvinyl)-3,1-benzoxathiin-4-ones through palladium–copper catalysis
作者:Bidisha Nandi、Nitya G. Kundu
DOI:10.1039/b102306n
日期:——
A palladiumâcopper-catalysed procedure for the synthesis of (E)-2-(2-arylvinyl)-3,1-benzoxathiin-4-ones 5aâ5h is developed. 3-[2-(Methoxycarbonyl)phenylthio]propyne 2 reacts with aryl iodides 3aâ3h in the presence of bis(triphenylphosphine)palladium(II) dichloride, copper(I) iodide and triethylamine in acetonitrile to furnish the disubstituted alkynes 4aâ4h in good yields (70â84%). These on alkaline hydrolysis and subsequent cyclisation of the carboxylic acids formed with copper(I) iodide (20 mol%) and triethylamine in tetrahydrofuran under reflux afford (E)-2-(2-arylvinyl)-3,1-benzoxathiin-4-ones 5aâ5h in 61â70% yield rather than the expected benzoxathiepinones 6. The reactions of (E)-2-(2-arylvinyl)-3,1-benzoxathiin-4-ones 5a and 5g with nucleophiles and the hydrogenation of compounds 5a, 5b and 5d are also studied.
开发了一种钯-铜催化的合成 (E)-2-(2-芳基乙烯基)-3,1-苯并噻唑-4-酮 5a–5h 的方法。3-[2-(甲氧羰基)苯基硫]丙炔 2 在二(三苯基磷)钯(II)氯化物、铜(I)碘化物和三乙胺存在下与芳基碘化物 3a–3h 反应,生成取代的炔烃 4a–4h,收率良好(70–84%)。这些在碱性水解后,与铜(I)碘化物(20 mol%)和三乙胺在四氢呋喃中回流反应,产生了 (E)-2-(2-芳基乙烯基)-3,1-苯并噻唑-4-酮 5a–5h,其收率为 61–70%,而不是预期的苯并噻幽啉酮 6。还研究了 (E)-2-(2-芳基乙烯基)-3,1-苯并噻唑-4-酮 5a 和 5g 与亲核试剂的反应,以及化合物 5a、5b 和 5d 的氢化反应。