AbstractsChemistry

Generating complexity by reductive electron transfer: asymmetric studies and cyclisation cascades

by Sarah Lyons




Institution: University of Manchester
Department:
Year: 2015
Keywords: samarium diiodide; asymmetric desymmetrisation; radical chemistry; single electron transfer; organic synthesis
Record ID: 1410046
Full text PDF: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:247431


Abstract

Reductive electron transfer has been successfully utilized to facilitate the first enantioselective desymmetrisation of malonate derivatives. Selective monoreduction of cyclic 1,3-diesters through the combined use of SmI2-Et3N and chiral non-racemic diols has granted rapid access to enantioenriched β-hydroxy acids containing challenging quaternary centres – an abundant motif in many drug molecules.Unique radical anions generated from the single electron reduction of cyclic 1,3-diesters have been exploited in cyclisation cascades. Capture of acyl-type radical anions by both alkene and alkyne acceptors have permitted the construction of complex bicyclic architectures in a single synthetic operation. The reductive cyclisation cascade of lactones has also been demonstrated, using SmI2-H2O to achieve a challenging domino 5-exo-trig/6-exo-trig cyclisation event. This process generates highly decorated carbo[5.4.0]bicyclic scaffolds with complete diastereocontrol.