New pathways of the Schmidt reaction and their synthetic applications

ORGN 122

Cong-Gui Zhao,, Rupak Chakraborty, Veronica Franz, and Ghanashyam Bez. Department of Chemistry, University of Texas at San Antonio, 6900 N. Loop 1604 W, San Antonio, TX 78249-0698
Lewis acid-catalyzed reaction of β-azidoalcohol and aldehyde normally gives 2-oxazoline as the product. This reaction is known as the Boyer reaction, which is one pathway of the Schmidt reaction. In our recent study of the reaction of azido alcohol and aldehyde, we identified some new pathways of the Schmidt reaction. For example, when 2-azido-2-phenylethanol is used as the substrate, 3-oxazoline is obtained instead, which enables us to develop the first enantioselective synthesis of these compounds. If Cu(OTf)2 is used as the Lewis acid catalyst, then acetals are obtained (Scheme 1). This methodology may be used for the synthesis of novel macrocyclic chiral ligands (Such as I) for metal-catalyzed reactions, such as CuBr-catalyzed addition of phenylacetylene to imine. The mechanisms of these new pathways and their synthetic significance will be discussed.