Reagent electrophilic ketoester

Togni and coworkers have found that 1-trifluoromethylbenziodoxole 770 is a useful reagent for electrophilic trifluoromethylation of nucleophilic substrates. This reagent, in particular, reacts with (3-ketoesters 769 under mild conditions in the presence of potassium carbonate to give a-trifluoromethylated product 771 in good yield (Scheme 3.303) [1026, 1027]. Likewise, this mild electrophilic trifluoromethylating... 

Togni. In the presence of 5 mol% of Ti[4 -bis(diphe-nyLhydroxymethyl)-2,2-dimethyldioxoIane (TADDOL)(ate)] complex 400, the catalytic sulfenylation was effected with phenylsulfenyl chloride 399 however, the use of other sulfe-nylating reagents such as phthalimde-iV-sulfenyl chloride led to a less selective product formation. " Most recently, Shi-bata et al. reported in 2009 on the synthesis of chiral a-sul-fenyl-(3-ketoesters 404 by an enantioselective electrophilic sulfenylation of a-fluoro-p-ketoesters 402 in the presence of a catalytic amount of (/ ,/ )-4,6-dibenzofiirandiyl-2,2 -bis(4-phenyloxazoline) (DBFOX)-Ph 403/Ni(ll) complex in mod-est-to-good yields and enantioselectivities. ... 

Gade reported the asymmetric trifluoromethylation of (3-ketoesters using copper catalysis in the presence of bisoxazoline ligands. Here, either Togni s or Umemoto s reagent was required as the CF3 electrophile source. Sodeoka " reported the copper catalysed trifluoromethylation of allylsilanes, as did... 

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