Affordable Access

Publisher Website

Preparation of tricyclic imidazopyridines by asymmetric ketone hydrogenation in the presence of RuCl2[(S)-Xyl-P-Phos][(S)-DAIPEN]

Authors
Journal
Tetrahedron Asymmetry
0957-4166
Publisher
Elsevier
Publication Date
Volume
19
Issue
11
Identifiers
DOI: 10.1016/j.tetasy.2008.05.013
Disciplines
  • Biology
  • Pharmacology

Abstract

Abstract The novel complex RuCl 2[( S)-Xyl-P-Phos][( S)-DAIPEN] was identified as a highly active catalyst for the asymmetric reduction of a variety of prochiral ketones possessing an imidazo[1,2- a]pyridine scaffold. The corresponding alcohols were obtained in excellent enantiomeric purities (>96% ee) and served as valuable intermediates for the synthesis of pharmacologically active 7 H-8,9-dihydropyrano[2,3- c]imidazo[1,2- a]pyridines. The complexity of these multi-functional substrates required the development of specific reaction conditions. Whereas the reduction with RuCl 2[PP][NN] catalysts (Noyori catalysts) has never been reported to occur under aqueous conditions, in the present case, the use of aqueous isopropanol or tert-butanol was not only tolerated, but also turned out to be beneficial, especially when the reduction was conducted at high substrate to catalyst (S/C) ratios.

There are no comments yet on this publication. Be the first to share your thoughts.