An easily accessed class of recyclable hypervalent iodide reagents for functional group oxidations:bis(trifluoroacetate)adducts of fluorous alkyl iodides,CF_3(CF_2)_(n-1)I(OCOCF_3)_2

摘要

Reactions of commercial fluorous alkyl iodides R_(fn)I(1-R_(fn);R_(fn)= CF_3(CF_2)_(n-1);n = 7,8,10,12)with 80% H_2O_2 and trifluoroacetic anhydride give R_(fn)I(OCOCF_3)_2(2-R_(fn);89-97%).These rapidly oxidize 1,4-hydroquinones in methanol.Subsequent additions of CF_3C_6F_(11)or FC-72 give liquid/liquid biphase systems.The product quinones are generally isolated in >=95% yields from the methanol phases,and 1-R_(fn),in >=95% yields from the fluorous phases.Alternatively,the very low solubilities of 1-R_(f10)in 10:1 v/v methanol:water or 1-R_(f12)in methanol allow efficient recovery via solid/liquid phase separations without recourse to fluorous solvents.The recovered 1-R_(fn),may be reoxidized to 2-R_(fn),and reused.