Enantioselective one-carbon expansion of aromatic rings by simultaneous formation and chromoselective irradiation of a transient coloured enolate

Rakesh K. Saunthwal, James Mortimer, Andrew J. Orr-Ewing, Jonathan Clayden*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

5 Citations (Scopus)
45 Downloads (Pure)

Abstract

Enantioenriched seven-membered carbocycles are motifs in many molecules of structural and biological interest. We report a simple, practical, transition metal-free and mechanistically unusual method for the enantioselective synthesis of substituted cycloheptatrienes. By forming a coloured enolate with an appropriate absorption band and selectively irradiating in situ, we to initiate a tandem, asymmetric anionic and photochemical ring expansion of readily accessible N-benzylbenzamides. The cascade of reactions leading to the products entails enantioselective benzylic deprotonation with a chiral lithium amide, dearomatizing cyclization of the resulting configurationally defined organolithium to give an extended amide enolate, and photochemically induced formal [1,7]-sigmatropic rearrangement and 6π-electrocyclic ring-opening – the latter all evidently being stereospecific – to deliver enantioenriched cycloheptatrienes with embedded benzylic stereocentres
Original languageEnglish
Pages (from-to)2079-2085
Number of pages7
JournalChemical Science
Volume13
Issue number7
Early online date25 Jan 2022
DOIs
Publication statusE-pub ahead of print - 25 Jan 2022

Bibliographical note

Funding Information:
This work was funded by the European Commission: Marie Sklodowska Curie individual fellowship (Grant No. 839739) to RKS and by the EPSRC Bristol CDT in Technology-Enhanced Chemical Synthesis (EP/S024107/1).

Publisher Copyright:
This journal is © The Royal Society of Chemistry

Structured keywords

  • BCS and TECS CDTs

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