Bis(amidate)bis(amido) titanium complex: a regioselective intermolecular alkyne hydroamination catalyst

J Org Chem. 2014 Mar 7;79(5):2015-28. doi: 10.1021/jo402668q. Epub 2014 Feb 21.

Abstract

An efficient and selective bis(amidate)bis(amido) titanium precatalyst for the anti-Markovnikov hydroamination of alkynes is reported. Hydroamination of terminal and internal alkynes with primary alkylamines, arylamines, and hydrazines is promoted by 5-10 mol % of Ti catalyst. Various functional groups are tolerated including esters, protected alcohols, and imines. The in situ generated complex shows comparable catalytic activity, demonstrating its synthetic versatility for benchtop application. Applications of this catalyst for the synthesis of amino alcohols and a one-pot procedure for indole synthesis are described. A mechanistic proposal that invokes turnover-limiting protonolysis is presented to rationalize the observed regioselectivities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry*
  • Amination
  • Catalysis
  • Imines / chemistry*
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis*
  • Titanium / chemistry*

Substances

  • Alkynes
  • Imines
  • Organometallic Compounds
  • Titanium