Single-isomer iodochlorination of alkynes and chlorination of alkenes using tetrabutylammonium iodide and dichloroethane

Michael L Ho; Alison B Flynn; William W Ogilvie

doi:10.1021/jo062188w

Single-isomer iodochlorination of alkynes and chlorination of alkenes using tetrabutylammonium iodide and dichloroethane

J Org Chem. 2007 Feb 2;72(3):977-83. doi: 10.1021/jo062188w.

Authors

Michael L Ho¹, Alison B Flynn, William W Ogilvie

Affiliation

¹ Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada K1N 6N5.

PMID: 17253819
DOI: 10.1021/jo062188w

Abstract

The efficient formation of single-isomer, differentially halogenated alkenes and alkanes is described. These structures were generated by treatment of the appropriate alkyne or alkene with tetrabutylammonium iodide in refluxing dichloroethane. This process is highly selective as evidenced by control experiments using ICl. Treatment of the same alkenes and alkynes directly with iodine monochloride resulted in complex, inseparable mixtures of regio- and stereoisomers. Mechanistic studies indicated that the Bu4NI reaction most likely proceeded through the slow generation of ICl. Complexation of ICl with Bu4NI is also a key controlling element that leads to perfect regio-, chemo-, and stereoselectivity in these processes.