Organocatalytic approaches to claisen rearrangements of acid sensitive substrates

Abstract

Cyclopentanes and cyclopentenes are present in many natural products and pharmaceuticals. Despite their presence in many natural products and pharmaceuticals there are few general methods to synthesize highly functionalized 5-membered carbocycles. Using substituted allyl vinyl ethers, highly functionalized 5-membered carbocycles can be accessed through a Claisen rearrangement followed by an intramolecular Sakurai reaction. Due to the acid sensitive nature of these allyl vinyl ethers, Lewis acid catalysis is not a viable reaction pathway but the use of H-bond donors as organocatalysts is an attractive method to develop a synthetic methodology to access 5-membered carbocycles. Through NMR and computational studies, the activation parameters of a these HBD catalyzed Claisen rearrangement has been studied and further knowledge into the mechanism of these reaction pathways has been gained.