Synlett 2013; 24(13): 1737-1738
DOI: 10.1055/s-0033-1338964
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© Georg Thieme Verlag Stuttgart · New York

Diiodomethane: A Versatile C1 Building Block

Cláudia Diana C. B. G. Raposo
REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal   Email: piccfa@gmail.com
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Further Information

Publication History

Publication Date:
17 July 2013 (online)

Introduction

Diiodomethane, better known as methylene iodide, is a dense (3.325 g/mL at 25˚C), light-sensitive, pale-yellow liquid. Because of its high density, it is used by the gemo­logical industry to determine the density of minerals.[1] Being such an interesting compound, diiodomethane is a versatile C1 building block, which can be used to form carbon–carbon and carbon–heteroatom bonds. It is an easy-to-handle compound and can be used in a wide number of different reactions such as epoxidation,[2] diazotization,[3] iodomethylation,[4] cyclopropanation,[5] alkene reduction,[6] and sigmatropic rearrangement.[7] In the presence of metallic samarium, the air-sensitive samarium diiodide (SmI2) is formed in situ; this is cheaper than buying samarium diiodide.[8]

Diiodomethane is commercially available, but can also be prepared by mixing methylene dichloride and sodium ­iodide in dimethylformamide at a constant temperature of 100 °C for 6–8 hours.[9]