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, CO(2) tBu, alkynyl, ethers, thioethers). Large-scale reactions (25-40 mmol) and the preparation of fully functionalised furans and thiophenes are also reported.

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 furan and thiophene scaffolds.

The aryl sulfoxide moiety (ArSO) allows an expedient two-step meta-, para-difunctionalization of readily available diaryl sulfoxides. In the first step, the sulfoxide plays the role of a directing metalation group. In the second step, triggered by i-PrMgCl x LiCl, it becomes a leaving group and undergoes a regioselective sulfoxide-magnesium exchange.

Functionalized alkylmagnesium reagents bearing an acetal, a ketal, an ester, or a pyridine ring were prepared by an I/Mg-exchange using iPr2Mg.LiCl or ClMg(CH2)5MgCl.2LiCl starting from functionalized primary alkyl iodides.

Highly functionalized 1,2,4-trisubstituted arenes can be prepared on large scale by a two-step sequence, triggered by an aryl sulfoxide group. In the first step, the sulfoxide moiety acts as a metalation directing group, allowing a smooth magnesiation with tmpMgCl·LiCl. After a quenching reaction with an electrophile, the resulting sulfoxide is converted with i-PrMgCl·LiCl into a second magnesium reagent (sulfoxide-magnesium exchange), which can be trapped with various electrophiles. The highly chemoselective tmpMgCl·LiCl and i-PrMgCl·LiCl are compatible with a broad range of functional groups (FG = F, Cl, CF 3 , CN, CO 2 t-Bu, alkynyl).