New Ring Expansion and Ring Opening Reactions of Vinyl Oxetanes and Vinyl Oxiranes

Abstract

Three new synthetic methods employing vinyl oxetanes as substrates are presented. In Chapter 2, a new catalytic vinyl oxetane ring expansion is described. Origins, design, reaction, and optimizations are discussed. A novel asymmetric synthesis of 3,6-dihydro-2H-pyrans using chiral counterion catalysis is presented as part of these studies. In Chapter 3, the Z-selective ring opening of vinyl oxetanes using dialkyl dithiophosphate nucleophiles is described from initial discovery, through optimizations to the application towards the synthesis of thiopyrans. These insights were then utilized to develop a similar Z-selective protocol for vinyl oxiranes. In Chapter 4, a novel method to synthesize homoallylic alcohols from 3,6-dihydro-2H-pyrans using a mild and selective C-O reduction approach is described.