Preparative Synthesis of Highly Substituted Tetrahydropyridines via a Rh(I)-Catalyzed C-H Functionalization Sequence
Tehetena Mesganaw1, Jonathan A Ellman1
1Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
Abstract:
We report a Rh(I)-catalyzed C-H activation/alkenylation/electrocyclization cascade and subsequent reduction for the synthesis of highly substituted tetrahydropyridines. These products can be accessed on a gram scale with low catalyst loadings and at high reaction concentrations. Additionally, a modified Rh-catalyst, prepared from [RhCl(cod)]2 as a robust bench-stable precatalyst was developed to enable straightforward reaction set up without the use of a glovebox. To demonstrate the practicality of this reaction, a >100 mmol scale Rh-catalyzed cascade reaction sequence utilizing the air-stable precatalyst [RhCl(cod)]2 was performed on the bench to furnish the pure tetrahydropyridine product in 93% yield.
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