Synlett 2015; 26(04): 501-507
DOI: 10.1055/s-0034-1379893
© Georg Thieme Verlag Stuttgart · New York

Thermal and Photochemical Mechanisms for Cyclobutane Formation in Bielschowskysin Biosynthesis

Bencan Tanga, b, Robert Simiona, c, Robert S. Paton*a, c
  • aChemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
  • bDepartment of Chemical and Environment Engineering, The University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315100, P. R. of China
  • cPhysical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK   Email:
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Publication History

Received: 04 November 2014

Accepted: 14 January 2015

Publication Date:
09 February 2015 (eFirst)


The unique structure of furanocembranoid natural product bielschowskysin has provoked a number of biosynthetic hypotheses: quantum chemical calculations provide a means to assess the feasibility of postulated mechanisms in the construction of this unusual carbon skeleton. Calculations reveal that thermal closure is possible in water via an unusual concerted cyclobutane-forming transition state without the intervention of an enzyme. Photocycloaddition is computed to be extremely efficient, provided enol ether triplet sensitization can be achieved by an appropriate light source. The possible existence of a stable dicarbonyl intermediate presents a challenge for the thermal route, implicating a photochemical pathway in bielschowskysin biosynthesis.

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