Balancing Lewis Acidity and Carbocation Stability for the Selective Deoxyhalogenation of Aryl Carbonyls and Carbinols
P. Veeraraghavan Ramachandran*, Abdulkhaliq A. Alawaed and Henry J. Hamann
*Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States,
Email: chandran
purdue.edu
P. V. Ramachandran, A. A. Alawaed, H. J. Hamann, Org. Lett., 2023, 25, 4650-4655.
DOI: 10.1021/acs.orglett.3c01462
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Abstract
Appropriate metal halide Lewis acids act as a carbonyl activator and halogen carrier for a deoxyhalogenation of aryl aldehydes, ketones, carboxylic acids, and esters in the presence of borane-ammonia as the reductant. Selectivity is accomplished by matching the stability of the carbocation intermediate with the effective acidity of the Lewis acid depending on the used solvent.
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proposed mechanism
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.
Key Words
benzylic chlorides, ammonia-borane
ID: J54-Y2023
