Diastereoselective Cyclizations of Enantiopure Planar Chiral N-Oxazolidinoyl Diene Iron(0) Tricarbonyl Complexes
Date of Award
© 2019 Colin C. Howell. All rights reserved. This work is freely available courtesy of the author. It may only be used for non-commercial, educational, and research purposes. For all other uses, including reproduction and distribution, please contact the copyright holder.
Bachelor of Arts
Chemistry & Biochemistry
Robert S. Paley
Iron(0) tricarbonyl diene complexes have long been established as effective stereodirecting groups due to their planar chirality and the steric bulk of the iron fragment. If initial diastereoselective complexation can be achieved, these molecules are therefore capable of acting as scaffolds for the stereoselective synthesis of architecturally complex products. The Paley laboratory uses chiral auxiliaries, most recently oxazolidinones, bound to acyclic dienes to assure diastereoselective complexation, before exploring the potential of diverse diastereomeric chemistry on the diene periphery. In this work we report progress on the development of an asymmetric, intramolecular rhodium(II)-catalyzed C-H insertion adjacent to the diene to form five- membered carbocycles with two determined stereocenters. In particular, we discuss the synthesis of N-oxazolidinoyl diene iron(0) tricarbonyl complexes containing both protected alcohol and indole functionalities, followed by diastereoselective cyclization to form the corresponding cyclopentenes upon addition of the rhodium catalyst. Additionally, initial steps towards the optimization of these synthetic pathways, including the exploration of alternative methods to install the requisite diazo group, are detailed in this report. It is predicted that these transformations will ultimately enable synthetic access to new classes of natural products.
Howell, Colin C. , '19, "Diastereoselective Cyclizations of Enantiopure Planar Chiral N-Oxazolidinoyl Diene Iron(0) Tricarbonyl Complexes" (2019). Senior Theses, Projects, and Awards. 239.