Biphasic Chlorination of Iodoarenes to (Dichloroiodo)arenes

Abstract

A two-phase (CCl 4 / conc. hydrochloric acid) chlorination of some iodoarenes to the corresponding (dichloroiodo)arenes, prepared in 50-98% crude yields, is reported. Dichlorine is produced in the aqueous phase as follows: KClO 3 (solid) + 6 HCl (conc. aq.) → ↑3Cl 2 + KCl + 3H 2 O

One-Pot Procedures for Preparing (Dichloroiodo)arenes from Arenes and Diiodine, with Chromium(VI) Oxide as the Oxidant

“…The melting points with decomposition (see Table 1 ) are uncorrected and were measured as follows: after an approximate mp had been taken in an open capillary tube, a new sample was introduced about 10 o C below this point, and the temperature was raised at a rate of 10 o C min -1 . Mps found by us ( Table 1 ) were fairly close to those reported in our former papers [ 5 , 6 , 7 , 8 , 9 ]. Iodometric titrations [ 2 ] of the freshly prepared ArICl 2 showed that they were of 91-97% purity.…”

Conversion of Aryl Iodides into Aryliodine(III) Dichlorides by an Oxidative Halogenation Strategy Using 30% Aqueous Hydrogen Peroxide in Fluorinated Alcohol

“…Nevertheless, 14b is unstable and 1 H-NMR analysis reveals clearly its rapid decomposition with concomitant ring chlorination. Interestingly, when using other oxidants like SPB [ 21 ], UHP [ 22 ], KClO 3 [ 17 ] or Na 2 S 2 O 3 [ 18 ] in combination with HCl, (dichloroiodo)-4-metoxybenzene ( 14b) is obtained in good yields, and there is no observable chlorination at the aromatic nucleus. In some cases CCl 4 was used rather than polar solvents [ 18 , 21 ].…”

“…Therefore, mono and biphasic oxidative procedures based on generating chlorine from concentrated hydrochloric acid used either as a separate phase or co-solvent in the presence of an oxidant have been developed [ 1 , 2 , 3 , 4 , 14 ]. Skulski and others have used strong oxidants, such as KMnO 4 , activated MnO 2 [ 16 ], KClO 3 [ 17 ], concentrated HNO 3 [ 16 ], Na 2 S 2 O 8 [ 18 ], CrO 3 [ 19 ], NaClO 2 and NaClO [ 20 ], usually in excess, to synthesize various (dichloroiodo) arenes. Oxidative methods for the synthesis of (dichloroiodo) arenes have also been extended to derivatives of hydrogen peroxide as safer, easier to handle and environmentally less harmful oxidants, like sodium perborate (NaBO 3 ·H 2 O or NaBO 3 ·4H 2 O, SPB) [ 16 , 21 ] sodium percarbonate (Na 2 CO 3 ·1.5H 2 O 2 , SPC) [ 16 ] and urea hydrogen peroxide (NH 2 CONH 2 ·H 2 O 2 , UHP) [ 16 , 22 ].…”

Catalytic Asymmetric Chlorination of β‐Keto Esters with Hypervalent Iodine Compounds

“…However, benzoyl derivative 3e and benzyl-and allyl-substituted esters 3f and 3g gave clearly lower enantioselectivities (Entries 5 ± 7). The use of 1-(dichloroiodo)-4-nitrobenzene [8] or 1-(dichloroiodo)-4-methoxybenzene [10] instead of 2 did not affect the stereoselectivity of the chlorination of 3a significantly. The use of 1-(dichloroiodo)-4-nitrobenzene [8] or 1-(dichloroiodo)-4-methoxybenzene [10] instead of 2 did not affect the stereoselectivity of the chlorination of 3a significantly.…”