Practical and General Alcohol Deoxygenation Protocol |
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Authors: | Oliver P Williams Alyah F Chmiel Myriam Mikhael Desiree M Bates Charles S Yeung Zachary K Wickens |
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Institution: | 1. Department of Chemistry, University of Wisconsin-Madison, Madison, WI-53706 USA;2. Discovery Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA-02115 USA |
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Abstract: | Herein, we describe a practical protocol for the removal of alcohol functional groups through reductive cleavage of their benzoate ester analogs. This transformation requires a strong single electron transfer (SET) reductant and a means to accelerate slow fragmentation following substrate reduction. To accomplish this, we developed a photocatalytic system that generates a potent reductant from formate salts alongside Brønsted or Lewis acids that promote fragmentation of the reduced intermediate. This deoxygenation procedure is effective across structurally and electronically diverse alcohols and enables a variety of difficult net transformations. This protocol requires no precautions to exclude air or moisture and remains efficient on multigram scale. Finally, the system can be adapted to a one-pot benzoylation-deoxygenation sequence to enable direct alcohol deletion. Mechanistic studies validate that the role of acidic additives is to promote the key C(sp3)?O bond fragmentation step. |
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Keywords: | Deoxygenation Formate Mesolytic Cleavage Photoredox Catalysis Reduction |
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