Categories: C=O Bond Formation >
Synthesis of ketones
A hypervalent iodine reagent, (diacetoxyiodo)benzene, and catalytic amount of sodium azide in acetonitrile enable an oxidative decarboxylation of 2-aryl carboxylic acids into the corresponding aldehydes, ketones, and nitriles in good yields at room temperature. The advantages of this protocol are short reaction times and mild reaction conditions.
V. N. Telvekar, K. A. Sasane, Synlett, 2010, 2778-2779.
Reactivity at the homobenzylic position can be accomplished using dual organic photoredox/cobalt catalysis. Through a two-part catalytic system, alkyl arenes undergo dehydrogenation followed by an anti-Markovnikov Wacker-type oxidation to provide benzyl ketone products. This formal homobenzylic oxidation is accomplished with high atom economy without the use of directing groups.
J. B. McManus, J. D. Griffin, A. R. White, D. A. Nicewicz, J. Am. Chem. Soc., 2020, 142, 10325-10330.
A copper-catalyzed oxidative cleavage reaction of terminal and internal alkynes using NFSI and TBHP provides aryl ketone products in good yields. NFSI not only functioned as N-centered radical precursor but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water.
L. Tang, F. Yang, H. Cheng, C. Tan, C. Jin, H. Chen, Y. Huang, S. Zhang, S. Zhang, W. Song, J. Tan, Org. Lett., 2020, 22, 8618-8623.
The use of visible-light-induced silver catalysis enables a controlled singlet-oxygen-mediated selective C-S bond cleavage reaction of benzyl thiols to afford carbonyl compounds.
B. Hong, K. C. C. Aganda, A. Lee, Org. Lett., 2020, 22, 4395–4399.
A commercial cyclopentadienylrutenium dicarbonyl dimer efficiently catalyzes the formation of N-H imines and carbonyl compounds simultaneously from β-hydroxy azides via C-C bond cleavage under visible light.
J. Min Lee, D. Y. Bae, J. Y. Park, H. Y. Jo, E. Lee, Y. H. Rhee, J. Park, Org. Lett., 2020, 22, 4608-4613.
Iron(III) acetylacetonate catalyzes an oxidative ring opening of cyclic ethers and acetals under visible light irradiation with unparalleled efficiency. This photocatalytic radical chemistry approach enables the conversion of relatively inert cyclic ethers into useful synthetic intermediates and illustrates that simple Fe(III) complexes can initiate redox processes from 4LMCT excited states.
R. Lindroth, A. Ondrejková, C.-J. Wallentin, Org. Lett., 2022, 24, 1662-1667.