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  • Visible Light-Gated Cobalt Catalysis for a Spatially and Temporally Resolved [2+2+2] Cycloaddition.

Visible Light-Gated Cobalt Catalysis for a Spatially and Temporally Resolved [2+2+2] Cycloaddition.

Journal of the American Chemical Society (2016-12-10)
Kyle E Ruhl, Tomislav Rovis
ABSTRACT

The ability to exert spatial and temporal control over a transition-metal catalyst offers diverse opportunities for the fabrication of functional materials. Using an external stimulus such as visible light to toggle a catalyst between an active and dormant state has proven to be an effective approach for controlled, radical methodologies. Outside of radical bond formation, there is a dearth of evidence that suggests traditional transition metal catalysis can similarly be controlled with visible light energy. Many cobalt complexes that catalyze the [2+2+2] cycloaddition are assisted by UV photolysis, but strict photocontrolled methods are unattainable due to high levels of thermally driven reactivity. Herein, we disclose the first light-controlled, cobalt-catalyzed [2+2+2] cycloaddition via a dual cobalt and photoredox catalyst manifold. We demonstrate the power of this method with a spatially and temporally resolved technique for arene formation using photolithography.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
CoCl2(PCy3)2