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New Batch of Oxazolines Derived Ligands for Asymmetric Synthesis

The unique properties of pyridine-oxazolines ligands are an important factor for catalytic activity

As we mentioned in our previous blog, oxazolines (Ox), related C2-symmetric bis-oxazolines (BOX) and especially their Pyridine derivatives (PyBox and PyOx or PyrOx) have been found as a powerful catalytic tool in asymmetric synthesis [1-4]. Extending of the pyridine ligand with the oxazoline ring will strongly influence the shape, the space, and the electronic properties of the central metal atom.

The electron-withdrawing groups are usually located at the 4- or 5-position, thus have no steric or coordinating interaction with the catalytic center. Substitution at the 3-position of the pyridine rings provides significant interaction between it and the oxazoline ring, thus increasing the dihedral angle between the pyridine ring and the oxazoline ring. The distortion provided by the additional group may have a significant impact on catalytic activity and enantioselectivity [4].


Fig.1. New chiral Py-Oxazoline and Bis(Oxazoline) ligands

Strem Catalog, by Ascensus Specialties in collaboration with Daicel, continues to introduce oxazoline derived chiral ligands that are widely employed in numerous asymmetric catalytic reactions. Some of the examples are shown on Fig. 1.  The unique properties of pyridine-oxazolines ligands have a big influence on catalytic activity.

PyrOx ligands have two coordination sites with distinct electronic properties, which should allow for a well-defined coordination environment envisioned to be required for effective asymmetric catalysis [5]. tBu- and iPr- oxazolyl pyridine ((S)t-BuPyOx 07-1044, (R)t-BuPyOx 07-1045 and (S)i-PrPyOx 07-1048, (R)t-BuPyOx 07-1049) are among the most popular PyrOx ligand. Detailed applications are available in the corresponding technical notes. Fluorinated PyrOx ligands, which are used e.g. in the Pd-catalyzed enantioselective Heck arylations of acyclic alkenyl alcohols [5] are also offered 07-1050; 07-7059; 07-1041.

Indane (07-1434; 07-1435; 07-1082; 07-1085) and Isoindole (07-1065; 07-1068; 07-1070) bridged bis-oxazolines are useful ligands for enantioselective fluorination, azidation, hydrosilylation, allylation, and intramolecular cyclization reactions (see technical notes). Chemical activities of other bis-oxazoline ligands (07-1058; 07-1062; 07-1073; 07-1076; 07-1079; 07-1088) are also available in corresponding technical notes.


  1. Adv. Synth. Catal., 2008, 350, 1023.
  2. Acc. Chem. Res., 2014, 47, 2260.
  3. Acc. Chem. Res., 2015, 48, 740.
  4. Chem. Soc. Rev., 2018, 47, 1783.
  5. Science, 2012, 338, 1455.

Featured Products:

07-1044 2-[(4S)-4-tert-Butyl-4,5-dihydro-2-oxazolyl]pyridine, 98%, (99% ee) (117408-98-7)

07-1045 2-[(4R)-4-tert-Butyl-4,5-dihydro-2-oxazolyl]pyridine, 95%, (99% ee) (242482-28-6)

07-1048  2-[(4S)-4,5-Dihydro-4-isopropyl-2-oxazolyl]pyridine, 98%, (99% ee) (108915-04-4)

07-1049 2-[(4R)-4,5-Dihydro-4-isopropyl-2-oxazolyl]pyridine, 98% (99% ee) (132187-16-7)

07-1050 2-[(4S)-4-tert-Butyl-4,5-dihydro-2-oxazolyl]-4-(trifluoromethyl)pyridine, 98% (1257527-14-2)

07-1058 2,2-Bis[(4R)-4-tert-butyl-2-oxazolin-2-yl]propane, 98%, (99% ee) (131833-97-1)

07-1434 (4R,4'R)-2,2'-(1,3-Dihydro-2H-inden-2-ylidene)bis[4,5-dihydro-4-isopropyloxazole], 98%, (99% ee)

07-1065 (1Z,3Z)-1,3-Bis[[(4R)-4,5-dihydro-4-phenyl-2-oxazolyl]methylene]-2,3-dihydro-1H-isoindole, 95% (1429056-54-1)


Related Product Lines & Materials:

Box Ligands
PyrOx Ligands
Pincer Ligands and Complexes



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