Iodine Monochloride

Biographical Sketches

Luana da Silva Magalhães Forezi was born in Recreio/MG, Brazil in 1984. She received her chemistry degree from the Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora/MG, Brazil in 2008. She is currently in the final stages of her M.Sc. studies in organic chemistry, at the Universidade Federal Fluminense, under the supervision of the Professors Maria Cecília Bastos Vieira de Souza and Fernanda da Costa Santos. Her research interests are focused on the synthesis of new compounds, such as ribonucleoside derivatives.

Introduction

Iodine monochloride is a chemical compound with the formula ICl. Because of the difference in the electronegativity of iodine and chlorine, ICl is highly polar and behaves as a source of I⁺. Iodine monochloride is a low melting black or brownish-red solid and widely available (usually in 97-98% purity). It is soluble in alcohol, ether, CS₂, acetic acid, acetone and pyridine and hydrolyzes in water to HCl and IOH. ICl explodes on contact with potassium metal, mixes with sodium metal, and it can explode if impacted. Its reaction with PCl₃ is extremely exothermic. [¹] Iodine monochloride can be easily prepared by adding an aqueous solution of potassium iodate to potassium iodate dissolved in concentrated HCl, in a closed vessel to avoid the loss of chlorine. [²] Iodine monochloride is a versatile reagent for the synthesis of a large number of organic compounds being employed, for example, as a source of electrophilic iodine in the synthesis of certain aromatic iodides. [³] It cleaves C-Si bonds [4] and can be used in the electrophilic addition to the double bond in alkenes leading to chloroiodoalkanes. [5] When iodine monochloride is reacted with sodium azide in situ, the iodoazide product is obtained. [6] Other examples of synthetic applications of this reagent also include electrophilic substitutions in Csp [²] and electrophilic cyclizations. [7-9]

Abstracts

(A) Do and Daugulis showed that the iodination of pentachlorobenzene using a combination of iodine chloride and t-BuOLi in DMF occurs in excellent yield (90%). Fluorine aromatic compounds like 1,3,5-trifluorobenzene can be either mono- or triiodinated in acceptable yields, depending on the ratio of the halobenzene to the iodine chloride. [³]
(B) Silylthiophene derivatives as 3,4-difluoro-2,5-bis(trimethylsilyl)thiophene can be submitted to an electrophilic substitution reaction with iodine chloride in anhydrous carbon tetrachloride to give 3,4-difluoro-2,5-diiodothiophene in 80% yield. [4]
(C) The addition of ICl to (Z)- and (E)-2-butene occurs in an anti-stereospecific manner: the erythro-2-chloro-3-iodobutane can be formed by the addition of ICl to (E)-1-butene, while the other isomer (threo) is formed by the addition of ICl to (Z)-1-butene. [5]
(D) In their research efforts to modify citidine nucleosides, Verheyden and Moffatt showed that the treatment of enol ether nucleoside 1 with iodine azide, generated in situ from iodine chloride and sodium azide, afforded the 4′-azido nucleoside derivative 1a. [6]
(E) Goodman et al. reported the reaction between 2β-carbo(2-fluoroethoxy)-3-{3′-[(Z)-2-trimethylstannylethenyl]phenyl}nortropane (2) and ICl, leading to compound 4 in good yield. Similar results were obtained in the case of 2β-carbo(2-fluoropropoxy)-3β-{3′-[(Z)-2-trimethylstannylethenyl]phenyl}nortropane (3). [7]
(F) A set of 4-iodoisocoumarins were efficiently prepared by electrophilic cyclization of ortho-(1-alkynyl)benzoates using iodine monochloride in dichlorometane. [8]
(G) Electrophilic cyclization of 2-chalcogene alkynyl anisole using ICl as an electrophile source produced 3-iodo-2-(phenylselanyl)benzofuran in good yield. Manarim et al. reported that for this type of reaction the product distributions were strongly dependent on the nature of the substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. [9]

References

• 1 Brisbois RG. Wanke RA. Stubbs KA. Stick RV. Iodine Monochloride, In Encyclopedia of Reagents for Organic Synthesis   John Wiley & Sons; West Sussex, UK: 2004. 
• 2 Beck MT. Ribai G. J. Phys. Chem.  1986,  90:  2204 
• 3 Do H. Daugulis O. Org. Lett.  2009,  11:  421 
• 4 Cardone A. Martinelli C. Pinto V. Babudri F. Losurdo M. Bruno G. Cosma P. Naso F. Farinola GM. J. Polym. Sci., Part A: Polym. Chem.  2010,  48:  285 
• 5 Schmida G. Gordon J. Can. J. Chem.  1986,  64:  2171 
• 6 Smith DB. Martin JA. Klumpp K. Baker SJ. Blomgren PA. Devos R. Granycome C. Heng J. Hobbs CJ. Jiang W. Laxton C. Pogam SL. Leveque V. Ma H. Maile G. Merrett JH. Pichota A. Sarma K. Smith M. Swallow S. Symons J. Vesey D. Najera I. Cammack N. Bioorg. Med. Chem. Lett.  2007,  17:  2570 
• 7 Stehouwer JS. Jarkas N. Zeng F. Voll RJ. Williams L. Camp VM. Malveaux EJ. Votaw JR. Howell L. Owens MJ. Goodman MM. J. Med. Chem.  2008,  51:  7788 
• 8 Roy S. Roy S. Neuenswamder B. Hill D. Larock RC. J. Comb. Chem.  2009,  11:  1128 
• 9 Manarim F. Roehrs JA. Gay RM. Brandão R. Menezes PH. Nogueira CW. Zeni G. J. Org. Chem.  2009,  74:  2153