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Stereo- and Chemodivergent NHC-Promoted Functionalisation of Arylalkylketenes with Chloral.

ABSTRACT: Stereo- and chemodivergent enantioselective reaction pathways are observed upon treatment of alkylarylketenes and trichloroacetaldehyde (chloral) with N-heterocyclic carbenes, giving selectively either ?-lactones (up to 88:12?dr, up to 94?%?ee) or ?-chloroesters (up to 94?%?ee). Either 2-arylsubstitution or an ?-branched iPr alkyl substituent within the ketene favours the chlorination pathway, allowing chloral to be used as an electrophilic chlorinating reagent in asymmetric catalysis.

SUBMITTER: Douglas JJ

PROVIDER: S-EPMC4648049 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Stereo- and Chemodivergent NHC-Promoted Functionalisation of Arylalkylketenes with Chloral.

Douglas James J JJ Churchill Gwydion G Slawin Alexandra M Z AM Fox David J DJ Smith Andrew D AD

Chemistry (Weinheim an der Bergstrasse, Germany) 20150925 46

Stereo- and chemodivergent enantioselective reaction pathways are observed upon treatment of alkylarylketenes and trichloroacetaldehyde (chloral) with N-heterocyclic carbenes, giving selectively either β-lactones (up to 88:12 dr, up to 94 % ee) or α-chloroesters (up to 94 % ee). Either 2-arylsubstitution or an α-branched iPr alkyl substituent within the ketene favours the chlorination pathway, allowing chloral to be used as an electrophilic chlorinating reagent in asymmetric catalysis. ...[more]

PMID: 26406613

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