title: Organic base effects in NHC promoted O- to C-carboxyl transfer; chemoselectivity profiles, mechanistic studies and domino catalysis.
abstract: The O- to C-carboxyl transfer of oxazolyl carbonates promoted by triazolinylidenes, generated in situ with NEt(3), shows a markedly different rate and chemoselectivity profile to the same reaction promoted by triazolinylidenes generated using KHMDS. The mechanism of these pathways has been probed through extensive crossover studies to understand this process. The use of NEt(3) as a base allows domino multi-step reaction sequences to be developed, although chiral NHCs only generate modest levels of asymmetric induction (<15% ee) in these domino reaction processes.
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK.
authors.forename: Craig D
authors.initials: CD
authors.lastname: Campbell
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Collett
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Thomson
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D002254:Carbonates / Q000737:chemistry*; D002384:Catalysis; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D002254:Carbonates; D006571:Heterocyclic Compounds; C030011:carbene; D008697:Methane