1176869-75-2Relevant academic research and scientific papers
Difunctionalisation of arenes and heteroarenes by directed metallation and sulfoxide-magnesium exchange
Melzig, Laurin,Rauhut, Christian B.,Naredi-Rainer, Nikolaus,Knochel, Paul
, p. 5362 - 5372 (2011/06/24)
The aryl sulfoxide moiety allows an expedient two-step difunctionalisation of readily available diaryl sulfoxides. Highly functionalised 1,2,4-trisubstituted arenes and difunctionalised heteroarenes (furans, thiophenes, benzofurans and pyridines) were prepared in a two-step sequence, triggered by an aryl sulfoxide group. In the first step, the sulfoxide moiety acts as a metallation-directing group, allowing smooth ortho-magnesiation with TMPMgCl.LiCl (TMP=tetramethylpiperidine). After a quenching reaction with an electrophile, the resulting sulfoxide is converted into a second magnesium reagent with iPrMgCl.LiCl (sulfoxide-magnesium exchange), which can be trapped with various electrophiles. Highly chemoselective TMPMgCl.LiCl and iPrMgCl.LiCl are compatible with a broad range of functional groups (e.g., F, Cl, CF 3, CN, CO2tBu, alkynyl, ethers, thioethers). Large-scale reactions (25-40 mmol) and the preparation of fully functionalised furans and thiophenes are also reported. Successful exchange: Highly functionalised 1,2,4-trisubstituted arenes and difunctionalised heteroarenes were prepared in a two-step sequence, triggered by an aryl sulfoxide group. The chemoselective reagents used, TMPMgCl.LiCl (TMP=tetramethylpiperidine) and iPrMgCl.LiCl, are compatible with a broad range of functional groups (see scheme; E=electrophile.)
2,3-Functionalization of furans, benzofurans and thiophenes via magnesiation and sulfoxide-magnesium exchange
Melzig, Laurin,Rauhut, Christian B.,Knochel, Paul
supporting information; experimental part, p. 3536 - 3538 (2009/12/02)
The use of TMPMgCl·LiCl and iPrMgCl·LiCl allows a sequential 2,3-difunctionalization of various 2-arylsulfinyl furans, thiophenes and benzofurans. Subsequent use of the same reagents permits a selective full functionalization of all 4 positions of the fur
