Mapping the Interactions of I2, I., I−, and I+ with Alkynes and Their Roles in Iodocyclizations

Volpe, Rohan, Aurelio, Luigi, Gillin, Murray G., Krenske, Elizabeth H. and Flynn, Bernard L. (2015) Mapping the Interactions of I2, I., I−, and I+ with Alkynes and Their Roles in Iodocyclizations. Chemistry - A European Journal, 21 28: 10191-10199. doi:10.1002/chem.201500384

Author Volpe, Rohan
Aurelio, Luigi
Gillin, Murray G.
Krenske, Elizabeth H.
Flynn, Bernard L.
Title Mapping the Interactions of I2, I., I−, and I+ with Alkynes and Their Roles in Iodocyclizations
Journal name Chemistry - A European Journal   Check publisher's open access policy
ISSN 0947-6539
Publication date 2015-06-01
Year available 2015
Sub-type Article (original research)
DOI 10.1002/chem.201500384
Open Access Status Not yet assessed
Volume 21
Issue 28
Start page 10191
End page 10199
Total pages 9
Place of publication Weinheim, Germany
Publisher Wiley - V C H Verlag GmbH
Language eng
Formatted abstract
A combination of experiment and theory has been used to explore the mechanisms by which molecular iodine (I2) and iodonium ions (I+) activate alkynes towards iodocyclization. Also included in the analysis are the roles of atomic iodine (I.) and iodide ion (I-) in mediating the competing addition of I2 to the alkyne. These studies show that I2 forms a bridged I2-alkyne complex, in which both alkyne carbons are activated towards nucleophilic attack, even for quite polarized alkynes. By contrast, I+ gives unsymmetrical, open iodovinyl cations, in which only one carbon is activated toward nucleophilic attack, especially for polarized alkynes. Addition of I2 to alkynes competes with iodocyclization, but is reversible. This fact, together with the capacity of I2 to activate both alkyne carbons towards nucleophilic attack, makes I2 the reagent of choice (superior to iodonium reagents) for iodocyclizations of resistant substrates. The differences in the nature of the activated intermediate formed with I2 versus I+ can also be exploited to accomplish reagent-controlled 5-exo/6-endo-divergent iodocyclizations.
Keyword Alkynes
Density Functional Calculations
Synthetic methods
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP110100835
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Chemistry and Molecular Biosciences
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Citation counts: TR Web of Science Citation Count  Cited 6 times in Thomson Reuters Web of Science Article | Citations
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Created: Fri, 05 Jun 2015, 19:41:11 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences