The mechanism of hydroaminoalkylation catalyzed by group 5 metal binaphtholate complexes

Alexander L. Reznichenko, Kai C. Hultzsch

Research output: Contribution to journalArticleScientificpeer-review

83 Citations (Scopus)

Abstract

The intermolecular hydroaminoalkylation of unactivated alkenes and vinyl arenes with secondary amines occurs readily in the presence of tantalum and niobium binaphtholate catalysts with high regio- and enantioselectivity (up to 98% ee). Mechanistic studies have been conducted in order to determine the kinetic order of the reaction in all reagents and elucidate the rate- and stereodetermining steps. The effects of substrate steric and electronic properties on the overall reaction rate have been evaluated. The reaction is first order in amine and the catalyst, while exhibiting saturation in alkene at high alkene concentration. Unproductive reaction events including reversible amine binding and arene C-H activation have been observed. The formation of the metallaaziridine is a fast reversible nondissociative process and the overall reaction rate is limited either by amide exchange or alkene insertion, as supported by reaction kinetics, kinetic isotope effects, and isotopic labeling studies. These results suggest that the catalytic activity can be enhanced by employing a more electron-deficient ligand backbone.

Original languageEnglish
Pages (from-to)3300-3311
Number of pages12
JournalJournal of the American Chemical Society
Volume134
Issue number6
DOIs
Publication statusPublished - 15 Feb 2012
MoE publication typeA1 Journal article-refereed

Fingerprint

Dive into the research topics of 'The mechanism of hydroaminoalkylation catalyzed by group 5 metal binaphtholate complexes'. Together they form a unique fingerprint.

Cite this