B(C6F5)3-Catalyzed Reductive Amination using Hydrosilanes

Valerio Fasano, James E. Radcliffe, Michael J. Ingleson*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

70 Citations (Scopus)
114 Downloads (Pure)

Abstract

In contrast to the established dogma that B(C6F5)3 is irreversibly poisoned by excess H2O/amine (or imine) bases, B(C6F5)3 is actually a water-tolerant catalyst for the reductive amination of primary and secondary arylamines with aldehydes and ketones in "wet solvents" at raised temperatures and using only 1.2 equiv of Me2PhSiH as reductant. Arylamines/N-arylimines do not result in the irreversible deprotonation of H2O-B(C6F5)3, allowing sufficient B(C6F5)3 to be evolved at raised temperatures to effect catalytic reductions. Stronger Brønsted basic amines such as tBuNH2 (and derived imines) result in irreversible formation of [HO-B(C6F5)3]- from H2O-B(C6F5)3, precluding the formation of B(C6F5)3 at raised temperatures and thus preventing any imine reduction. A substrate scope exploration using 1 mol % nonpurified B(C6F5)3 and "wet solvents" demonstrates that this is an operationally simple and effective methodology for the production of secondary and tertiary arylamines in high yield, with imine reduction proceeding in preference to other possible reactions catalyzed by B(C6F5)3, including the dehydrosilylation of H2O and the reduction of carbonyl moieties (e.g., esters).

Original languageEnglish
Pages (from-to)1793-1798
Number of pages6
JournalACS Catalysis
Volume6
Issue number3
Early online date16 Feb 2016
DOIs
Publication statusPublished - 4 Mar 2016

Keywords

  • "frustrated Lewis pairs"
  • amines
  • metal-free
  • reductive amination
  • water tolerance

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