Improved Methodology for the Preparation of Chiral Amines
Improved Methodology for the Preparation of Chiral Amines
Improved Methodology for the Preparation of Chiral Amines
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Reductive amination is a step powerful methodology <strong>for</strong> <strong>the</strong> syn<strong>the</strong>sis <strong>of</strong> α-chiral amines. The<br />
correct choice <strong>of</strong> Lewis acid is critical <strong>for</strong> efficient suppression <strong>of</strong> alcohols. The<br />
diastereoselectivity obtained with or without <strong>the</strong> use <strong>of</strong> Lewis acids was <strong>the</strong> same. No<br />
precedent <strong>of</strong> increasing diastereoselectivity in reductive amination with <strong>the</strong> use <strong>of</strong> achiral<br />
Lewis acid was ever reported. The use <strong>of</strong> Yb(OAc) 3 in reductive amination resulted in a<br />
significant increase in diastereoselectivities <strong>for</strong> different 2-alaknones. Diastereoselectivity <strong>of</strong><br />
2-octanone increased 15% compared to <strong>the</strong> highest reported result. Aromatic and cyclic<br />
ketones were not successfully reductively aminated using Yb(OAc) 3 . Ti(O i Pr) 4 proved to be<br />
<strong>the</strong> best Lewis acid in reductive amination <strong>of</strong> <strong>the</strong>se substrates.<br />
5.3. References:<br />
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116