Potassium tert-butoxide-mediated synthesis of unsymmetrical diaryl ethers, sulfides and selenides from aryl bromides

作者：Kumar Amit; Bhakuni Bhagat Singh; Prasad Ch Durga; Kumar Shailesh; Kumar Sangit

来源：Tetrahedron, 2013, 69(26): 5383-5392.

DOI：10.1016/j.tet.2013.04.113

Potassium tert-butoxide mediated carbon-chalcogen C-E (E=O, S and Se) coupling reaction has been studied from aryl bromide and phenol/aryl disulfide/diselenide substrates. A series of unsymmetrical diary] chalcogenides were accessed from aryl bromide and diary! dichalcogenide precursors by using 2.5 equiv of potassium tert-butoxide in DMSO at 80 degrees C. Unsymmetrical diaryl ethers were also obtained by using phenol precursors at 40-45 degrees C. Aryl bromides with methyl, trifluoromethyl, methoxy and nitro substituents showed compatibility in the carbon-chalcogen bond forming reaction. 4-Methoxy, methyl, trifluoromethyl substituted bromobenzene substrates gave two regioisomers: 3-substituted and 4-substituted diaryl chalcogenides when reacted with phenols/diaryl disulfides/diselenides. Formation of two regioisomeric diaryl chalcogenides in the reaction mixture suggests that potassium tert-butoxide reacts with bromobenzene to produce benzyne intermediate, which subsequently reacts with diary! dichalcogenides and finally give a regioisomeric mixture of 4-substituted and 3-substituted diary] chalcogenides.

• 出版日期2013-7-1