A DFT Study on the Conversion of Aryl Iodides to Alkyl Iodides: Reductive Elimination of R−I from Alkylpalladium Iodide Complexes with Accessible β‐Hydrogens. Issue 10 (25th January 2016)

• Record Type: Journal Article
• Authors: Hao, Wei; Wei, Junnian; Chi, Yue; Walsh, Patrick J.; Xi, Zhenfeng
• Is Part Of: Chemistry. Volume 22:Issue 10(2016)
• Page Start: 3422
• Page End: 3429
• Publication Date: 2016-01-25
• Subjects: alkylpalladium iodide complexes -- computational chemistry -- reaction mechanisms -- reductive elimination -- synthetic methods; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201503910
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: DFT calculations have been performed on the palladium‐catalyzed carboiodination reaction. The reaction involves oxidative addition, alkyne insertion, C−N bond cleavage, and reductive elimination. For the alkylpalladium iodide intermediate, LiO t Bu stabilizes the intermediate in non‐polar solvents, thus promoting reductive elimination and preventing β‐hydride elimination. The C−N bond cleavage process was explored and the computations show that PPh3 is not bound to the Pd center during this step. Experimentally, it was demonstrated that LiO t Bu is not necessary for the oxidative addition, alkyne insertion, or C−N bond cleavage steps, lending support to the conclusions from the DFT calculations. The turnover‐limiting steps were found to be C−N bond cleavage and reductive elimination, whereas oxidative addition, alkyne insertion, and formation of the indole ring provide the driving force for the reaction. Abstract : Reductive elimination versus β‐H elimination : DFT calculations have been performed on the palladium‐catalyzed carboiodination reaction. For the alkylpalladium iodide intermediate, LiO t Bu stabilizes the intermediate in non‐polar solvents, thus promoting reductive elimination and preventing β‐hydride elimination (see scheme).