A new non-natural chiral auxiliary: design, synthesis, and resolution of 1-mesitylethylamine and its application in the asymmetric aza-Diels-Alder reaction

1-Mesitylethylamine was designed as a new non-natural chiral auxiliary. Rac emic 1-mesitylethylamine could be synthesized in two steps from mesityl cya nide and could be resolved via separation of diastereomeric carbamates deri ved from (-)-menthyl chloroformate, followed by reduction with DIBAL and ac idic hydrolysis. Imines, prepared from enantiopure 1-mesitylethylamine and aromatic aldehydes, reacted with Danishefsky's diene in the presence of a L ewis acid to give cycloaddition products, 4-pyridone derivatives, with high diastereoselectivity. (C) 2000 Elsevier Science Ltd. All rights reserved.