Catalyst- and Stoichiometry-Dependent Deoxygenative Reduction of Esters to Ethers or Alcohols with Borane-Ammonia

P. Veeraraghavan Ramachandran* Abdulkhaliq A. Alawaed and Henry J. Hamann

*Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States, Email: chandranpurdue.edu

P. V. Ramachandran, A. A. Alawaed, H. J. Hamann, Org. Lett., 2023, 25, 6902-6906.

DOI: 10.1021/acs.orglett.3c02643

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Abstract

TiCl₄ mediates a facile and selective room temperature deoxygenation of both aromatic and aliphatic carboxylic esters to ethers in the presernce of BH₃-NH₃. This process is compatible with various potentially sensitive functional groups. Substituting TiCl₄ by BF₃-Et₂O  alters the reaction pathway, reducing esters to alcohols.

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proposed mechanism

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A Safer Reduction of Carboxylic Acids with Titanium Catalysis

P. V. Ramachandran, A. A. Alawaed, H. J. Hamann, Org. Lett., 2022, 24, 8481-8486.

TiCl₄-Catalyzed Hydroboration of Ketones with Ammonia Borane

P. V. Ramachandran, A. A. Alawaed, H. J. Hamann, J. Org. Chem., 2022, 87, 13259-13269.

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Key Words

ethers, alcohols, ammonia borane

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ID: J54-Y2023