Download PDF
Synlett 2011(8): 1186-1187  
DOI: 10.1055/s-0030-1259950
SPOTLIGHT
© Georg Thieme Verlag Stuttgart ˙ New York

Sodium Iodide

Vinícius Rangel Campos*
Instituto de Química, Universidade Federal Fluminense, UFF, CEP: 24020-141 Niterói, Rio de Janeiro, Brazil
e-Mail: viniciusquimicauff@hotmail.com ;
Further Information

Publication History

Publication Date:
20 April 2011 (online)

   Permissions and Reprints All articles of this category

Introduction

Sodium iodide (NaI) occurs as colorless, odorless or as a white crystalline solid; it is slightly hygroscopic, and a commercially available reagent. It is soluble in water, ­alcohols, acetone, and other organic solvents and stable under normal temperature and pressure (mp: 651 ˚C, d = 3.67 g/cm³). [¹] On a laboratory scale, sodium iodide may be prepared by neutralizing a solution of sodium hydroxide or sodium carbonate with hydriodic acid. [²] Sodium iodide is a very useful and versatile reagent for the synthesis of various types of organic compounds. For example, an important application of this reagent involves the conversion of an alkyl chloride or alkyl bromide to an alkyl iodide by the addition of sodium iodide in acetone (Scheme  [¹] ). [³] This nucleophilic substitution reaction, also known as Finkelstein reaction, may proceed via either an SN1 or SN2 mechanism depending on the nature of the alkyl halide. [4] [5]

Scheme 1

This reaction has been expanded to include the conversion of alcohols into alkyl halides by first converting the alcohol into a sulfonate ester (tosylates or mesylates are usually used), and then performing the substitution. [6] Other applications using sodium iodide as reagent in organic synthesis have been reported. They include the Finkelstein rearrangement-elimination reaction of 2-chloro-1-(chloromethyl)ethyl esters induced by NaI, [7] the Diels-­Alder reaction between α,α,α′,α′′-tetrabromo-oxylene and 2-cyclopentenone in the presence of NaI, [8] monoiodination of arenes by alkali metal iodide, [9] transformation of azides to primary amines using the CeCl3˙7H2O/NaI system, [¹¹] and Michael addition of nucleophiles to alkenes promoted by the CeCl3˙7H2O/NaI system supported on alumina. [¹²]