Bis(oxazoline) Pyridine Derivatives Have Been Found to be Effective Ligands for Enantioselective Transformations PyBOX Ligands for Asymmetric Catalysis

Bis(oxazoline) Pyridine Derivatives Have Been Found to be Effective Ligands for Enantioselective Transformations PyBOX Ligands for Asymmetric Catalysis

PyBOX Ligands for Asymmetric Catalysis

PyBOX represents a very important subgroup of bis(oxazoline) (BOX) ligands for asymmetric synthesis. Often in PyBOX two enantiomeric oxazoline rings containing a bulky substituent at the 4- and/or the 5-carbon positions are bridged with the pyridine, forming a C2 symmetrical molecule.

PyBOX is a tridentate “pincer-type” ligand and able to coordinate with a wide range of metals including alkaline earth, d- and f-transition metal atoms. Upon coordination of oxazoline rings through the N atoms, two stereogenic centers are produced near the metal centre.  This can influence and control the enantioselective process.

Pyridine-linked bis(oxazoline) ligands were introduced by Hisao Nishiyama in 1989. He used RuCl3/(S)-(i-Pr)-PyBOX (07-0307) CAS 118949-61-4 catalyst for asymmetric hydrosilylation of ketones[2]. (R)-isomer of (i-Pr)-PyBOX (07-0306) CAS 131864-67-0  is also highly effective in enantioselective transformations, e.g. Mannich reaction[3].

 

Today PyBOX ligands exist with a wide range of structural diversities. Metal complexes incorporating Phenyl [(R,R)-Ph-PyBOX (07-0303) CAS 128249-70-7S,S)-Ph-PyBOX (07-0304)]   CAS 174500-20-0 (R) 07-0390  CAS 365215-38-9 and (S) 07-0391] CAS 151670-69-8   and Indenyl-PYBOX (07-0280) CAS 185346-09-2 ligands are effective enantioselective catalysts for a variety of asymmetric synthesis.

 

For more detailed descriptions of each catalytic process please review the corresponding technical note for each item on our website.

 

References:

  1.       Chem. Rev., 2006, 106, 3561.; Chem. Rev. 2011, 111, PR284
  2.       Organometallics, 1989, 8, 846.
  3.       Organometallics, 1991, 10, 500.
  4.       Chem. Eur. J., 2013, 19, 10142.

 

 Visit the below links to view related oxazoline literature on our website:

SaBox and TOX Ligands

SpinPhox-Ir Catalyst Kit