Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity.

The title molecules are sought in connection with various synthetic applications. The aliphatic fluorous alcohols R CHOH (R = CF(CF) ; = 11, 13, 15) are converted to the triflates R CHOTf (TfO, pyridine; 22-61%) and then to R CHI (NaI, acetone; 58-69%). Subsequent reactions with NaOCl/HCl give iodine(III) dichlorides R CHICl ( = 11, 13; 33-81%), which slowly evolve Cl. The ethereal fluorous alcohols CFCFCFO(CF(CF)CFO) CF(CF)CHOH ( = 2-5) are similarly converted to triflates and then to iodides, but efforts to generate the corresponding dichlorides fail. Substrates lacking a methylene group, R I, are also inert, but additions of TMSCl to bis(trifluoroacetates) R I(OCOCF) appear to generate R ICl, which rapidly evolve Cl. The aromatic fluorous iodides 1,3-RCHI, 1,4-RCHI, and 1,3-RCHI are prepared from the corresponding diiodides, copper, and R I (110-130 °C, 50-60%), and afford quite stable R CHICl species upon reaction with NaOCl/HCl (80-89%). Iodinations of 1,3-(R)CH and 1,3-(RCHCH)CH (NIS or I/HIO) give 1,3,5-(R)CHI and 1,2,4-(RCHCH)CHI (77-93%). The former, the crystal structure of which is determined, reacts with Cl to give a 75:25 ArICl/ArI mixture, but partial Cl evolution occurs upon work-up. The latter gives the easily isolated dichloride 1,2,4-(RCHCH)CHICl (89%). The relative thermodynamic ease of dichlorination of these and other iodine(I) compounds is probed by DFT calculations.