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

12 Scopus citations

Abstract

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
Volume9
Issue number5
DOIs
StatePublished - 1 Jan 2018

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