Guiding a divergent reaction by photochemical control: Bichromatic selective access to levulinates and butenolides

Revannath L. Sutar, Saumik Sen, Or Eivgi, Gal Segalovich, Igor Schapiro, Ofer Reany, N. Gabriel Lemcoff

Research output: Contribution to journalArticlepeer-review


Allylic and acrylic substrates may be efficiently transformed by a sequential bichromatic photochemical process into derivatives of levulinates or butenolides with high selectivity when phenanthrene is used as a regulator. Thus, UV-A photoinduced cross-metathesis (CM) couples the acrylic and allylic counterparts and subsequent UV-C irradiation initiates E-Z isomerization of the carbon-carbon double bond, followed by one of two competing processes; namely, cyclization by transesterification or a 1,5-H shift and tautomerization. Quantum chemical calculations demonstrate that intermediates are strongly blue-shifted for the cyclization while red-shifted for the 1,5-H shift reaction. Hence, delaying the double bond migration by employing UV-C absorbing phenanthrene, results in a selective novel divergent all-photochemical pathway for the synthesis of fundamental structural motifs of ubiquitous natural products.

Original languageEnglish
Pages (from-to)1368-1374
Number of pages7
JournalChemical Science
Issue number5
StatePublished - 2018

Bibliographical note

Funding Information:
The Israel Science Foundation is gratefully acknowledged for a F.I.R.S.T. grant 1067/15 (OR and NGL) and an individual ISF grant 537/14 (NGL) that funded this research. The Open University is acknowledged for partial nancial support. I. S. gratefully acknowledges funding by European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 678169 “PhotoMutant”).

Publisher Copyright:
© The Royal Society of Chemistry 2018.


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