A Kinetic Understanding of the Reactivity and Structural Trends of Cyclopropylcarbinyl Type Ring Openings

Abstract

Page 1 of 26 Abstract The understanding of cyclopropylcarbinyl type ring openings is increasing because of the usefulness they pose as radical clocks 1. This leads to an increased qualitative understanding of the factors that regulate the reactivity of the ring opening. Additionally, this information will lead to a way to predict rate constants for specific systems. The ring opening of radical cyclopropylcarbinyls takes place through an ECE reaction mechanism. By comparing radical anion ring openings to their comparable neutral radical ring openings, basic kinetic data can be determined for the ring opening of cyclopropyl containing radical anions from structural data. This can then lead to the determination of the rate limiting step in the ECE mechanism, which in turn leads to basic thermodynamic data for the cyclopropylcarbinyl system. With the knowledge from the thermodynamic data, a plot can be created based upon the rate constant and free energy of the reaction. The plot is able to predict the rate constants for similar systems, which allows for a more universal use of the results presented.