Investigations of Strained Truce-Smiles Rearrangements

Abstract

The Truce-Smiles rearrangement is an aryl ring migration that occurs via an intramolecular SNAr pathway and concludes with the formation of a new C-C bond. The widely accepted mechanism for which is thought to proceed through a spirocyclic Meisenheimer intermediate, with the most frequently reported reactions involving the five-membered ring formation. Reports of alternative spirocyclic ring sizes vary in success and though they have been reported their presence is much less widespread. The opportunity for expansion in these under-developed areas was considered and investigations into the four-membered ring transition state Truce-Smiles rearrangement followed. Sulfonamides bearing deactivated aryl rings paired with substituted chloro-ethyl esters were able to achieve a tandem addition/Truce-Smiles rearrangement reaction through the strained 4-membered cyclic transition state under mild conditions. A variety of substitutions led to the synthesis of a range of free amines, imines and malonates which also had the potential to be incorporated into biocatalytic processes, for example enantioselective decarboxylation and asymmetric reduction. Further investigations attempted to explore asymmetric and radical approaches to the Truce-Smiles rearrangement, which have been documented to some extent for the five-membered intermediates but not for the four-membered intermediate.

Date of Award	1 Aug 2020
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Jason Micklefield (Supervisor) & Michael Greaney (Supervisor)