Selective electrochemical synthesis and reactivity of functional benzylic fluorosilylsynthons

Picking One out of Three: Selective Single C−F Activation in Trifluoromethyl Groups

“…[5a, 12] This finding can be di- rectly relatedt ot he higherr eactivity of CF 2 Ro rC FR 2 groups comparedt ot he CF 3 moiety (Figure 1), hence the difficulty to stop the reactiona fter the first transformation.N evertheless, some reports based on electrochemical reductions showed the possibility of single CÀFa ctivationi nC F 3 -arenes and as mall number of Mg 0 mediated reactions were published (Scheme 1c). [13,14] It should be noted that there are also some reports on single CÀFa ctivation processes not involving p-electron systems. Trifluoroethyl derivatives with as tabilizing group in the a-position (OTs, halide,p hosphine) can be readily deprotonated to furnish difluorovinyl organometallic complexes which can react with electrophiles to afford 1,1-difluoroalkenes (Scheme 1d).…”

Preparation of (Phenyldifluoromethyl)- and (Phenoxydifluoromethyl)-silanes by Magnesium-Promoted Carbon-Chlorine Bond Activation

“…[5][6][7] An electrochemical method has also been reported for its preparation from trifluoromethylbenzene. 8,9 In order to find an alternative synthesis, which could be more easily scaled up, we have examined Gilman's procedure for the formation of reagent 2. Similarly, we have studied the transformation of a-chloro-a,a-difluoroanisole (5) in analogous conditions in order to obtain the unknown (phenoxy-difluoromethyl)trimethylsilane (3, Figure 2).…”

Nucleophilic displacement versus electron transfer in the reactions of alkyl chlorosilanes with electrogenerated aromatic anion radicals

“…3). Silaphilic additives such as DMPU (tetrahydro-1,3-dimethyl-2(1H)-pyrimidinone), HMPA or DMF were commonly used in organosilicon electrosynthesis and voltammetry [32,33,36,[39][40][41][42] though their effect on the process studied is quite difficult to quantify.…”