Concerted C-N/C-H Bond Formation in Highly Enantioselective Yttrium(III)-Catalyzed Hydroamination

TitleConcerted C-N/C-H Bond Formation in Highly Enantioselective Yttrium(III)-Catalyzed Hydroamination
Publication TypeJournal Article
Year of Publication2011
AuthorsManna K, Kruse ML, Sadow AD
Journal TitleACS Catalysis
Volume1
Pages1637-1642
Date Published11
Type of ArticleArticle
ISBN Number2155-5435
Accession NumberWOS:000296598000022
Keywordsaminoalkene, assessment, complexes, comprehensive computational, ENANTIOSELECTIVITY, hydroamination, hydroamination/cyclization, hydrogenation, intramolecular aminoalkene, mechanism, mediated, organolanthanide-catalyzed hydroamination, organometallics, POLYMERIZATION, pyrrolidine, rare-earth, unprotected amino olefins
Abstract

A highly active oxazolinylborato yttrium hydroamination catalyst provides 2-methyl-pyrrolidines with excellent optical purities. The proposed mechanism, in which a yttrium(amidoalkene)amine complex reacts by concerted C-N and C-H bond formation, is supported by the rate law for conversion, substrate saturation under initial rates conditions, kinetic isotope effects, and isotopic perturbation of enantioselectivity. These features are conserved between oxazolinylborato Mg-, Y-, and Zr-mediated aminoalkene cyclizations, suggesting related transition states for all three systems. However, inversion of the products' absolute configuration between yttrium and zirconium catalysts coordinated by the same 4S-oxazolinylborate ligands highlight dissimilar mechanisms of stereoinduction.

DOI10.1021/cs200511z
Alternate JournalACS Catal.