Synlett 2024; 35(09): 952-956
DOI: 10.1055/a-2201-7141
cluster
Chemical Synthesis and Catalysis in Germany

Chemoselective Reduction of Barbiturates by Photochemically Excited Flavin Catalysts

Richard Foja
,
Alexandra Walter
,
Golo Storch
The Fonds der Chemischen Industrie (FCI, PhD Fellowship to A.W. and Liebig Fellowship to G.S.) is gratefully acknowledged. R.F. thanks the Studienstiftung des Deutschen Volkes for a PhD fellowship. G.S. thanks the Deutsche Forschungsgemeinschaft (DFG) for support through the Emmy Noether Programme (STO 1175/3-1) and the TRR 325 (444632635, Project B7).


Abstract

Photocatalytic reductive cyclizations are powerful methods for obtaining structurally complex molecules. Achieving noninherent reactivity in substrates with more than one potential site of reduction is a difficult challenge. We disclose the use of flavin catalysis for the chemoselective reductive cyclization of barbiturates with additional reactive functional groups. Our method provides orthogonal selectivity in comparison to the well-established reductant samarium(II) iodide, which preferentially reduces substrate ketone groups. Flavin catalysis first leads to barbiturate reduction and allows a complete change of chemoselectivity in barbiturates with appended ketones. Additionally, flavin photocatalysis enables the reductive cyclization of substrates with appended oxime ethers in >99% yield, which is not possible with SmI2.

Supporting Information

Primary Data



Publication History

Received: 19 September 2023

Accepted after revision: 30 October 2023

Accepted Manuscript online:
30 October 2023

Article published online:
08 December 2023

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