TETRAHEDRON-ASYMMETRY, cilt.26, ss.152-157, 2015 (SCI-Expanded)
A new class of quinazoline-based enantiomerically pure aziridine diols 4a-d were prepared from the aziridination of mesityl oxide 3 with in situ generated 3-acetoxyaminoquinazolinone (S)-2b followed by NaBH4 reduction. Aziridine diols 4a-d were purified by means of column chromatography on silica gel and their stereochemistries were assigned by X-ray crystallography and NMR analysis. These aziridine diols 4 were evaluated as chiral ligands in the asymmetric addition of diethylzinc to aryl aldehydes, and ligand (S,R,R)-4a yielded (R)-1-phenylpropanol derivatives with up to 92% ee, while the diastereomer (S,S,R)-4c gave the opposite enantiomers (S)-1-phenylpropanol derivatives with up to 86% ee. The results demonstrate that switching the configuration of the aziridine alcohol moiety in ligand gives a remarkable reversal of enantioselectivity in the asymmetric addition of diethylzinc to aryl aldehydes. (C) 2015 Elsevier Ltd. All rights reserved.