Reactions of Diketones and N-Allenoyloxazolidinones Catalyzed by Metal-Bis(oxazoline) Complexes

Abstract

This dissertation describes the investigation of the utility of metal–bis(oxazoline) complexes in catalytic asymmetric reactions. The development of Cu(II)-catalyzed regio- and enantioselective additions of silylketenthioacetals into diketones is discussed in the first chapter. (Cu(OTf)_2(t-BuBox)) complexes were found to be an effective catalyst with a broad substrate scope, providing tertiary alcohols in high yields, regioselectivities, and enantioselectivities. A model that accounts for the absolute stereochemistry of the product based on A1,3–interaction was proposed. Relative reactivities among diketones were also investigated. The second chapter reports the investigation of Diels–Alder reactions of N-allenoyloxazolidinones. The reaction between 3-buta-2,3-dienoyloxazolidin-2-one and cyclopentadiene was catalyzed by (Cu(SbF_6)_2(H_2O)_2(t-BuBox)) complexes, providing the cyclic product in high yield and enantioselectivity. The endo isomer was obtained as a major product with high selectivity. Relative reactivity between N-allenoyl oxazolidinones and unsaturated N-acyloxazolidinones was also studied.