In this mini-review, the main synthetic routes used in the preparation of oxazolines is presented.
The review is systematically carried out and the syntheses are presented in terms of precursors
utilised (nitriles, aldehydes and carboxylic acids). Additionally, the reported synthesis of all chiral and
achiral oxazolines involve either the use of amino alcohols as essential building blocks or some form
of intramolecular cyclisation reactions. A comparison of the effectiveness of various reaction initiators
such as Lewis acids, bases, oxidants and metals as well as their respective reaction conditions is also
described. Lewis acid catalysts such as zinc chloride, zinc oxide and indium (III) chloride as well as
triflic acid and ruthenium complexes are presented as effective catalysts in the formation of oxazolines
from nitrile precursors. Oxidising agents such as N-bromosuccinimide, hypervalent iodine reagents
and reducing agents such as butyllithium have been used in the formation oxazolines from aldehydes.
While carboxylic acids have been used effectively as good precursors to oxazolines when
using reagents such as cyanuric chloride as well as transition metal containing catalysts such as copper,
ruthenium and titanium. In some cases, catalyst free reaction conditions have also been reported
offering substituted oxazolines through microwave and ultrasonic irradiation as well as under standard
Keywords: Amino alcohol, catalysis, chirality, oxazoline, asymmetric reactions, microwave irradiation, synthesis.
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