Synthesis of ketones by oxidation of alkenes
The synergistic effect of photocatalysis and proton-reduction catalysis enables an unprecedented dehydrogenative oxygenation of β-alkyl styrenes and their derivatives with water under external-oxidant-free conditions. This dual catalytic system possesses the single anti-Markovnikov selectivity due to the property of the visible-light-induced alkene radical cation intermediate.
G. Zhang, X. Hu, C.-W. Chiang, H. Yi, P. Pei, A. K. Singh, A. Lei, J. Am. Chem. Soc., 2016, 138, 12037-12040.
Utilizing the full potential of IBX, a mild, selective, and facile method enables a direct conversion of olefins into the corresponding α-bromo ketones in the presence of 1.1 equivalents each of o-iodoxybenzoic acid and tetraethylammonium bromide.
S. S. Deshmukh, K. H. Chaudhari, K. G. Akamanchi, Synlett, 2011, 81-83.
In a Co-catalyzed reaction for the construction of 1,4-dicarbonyls, a cascade organocobalt addition/trapping/Kornblum-DeLaMare rearrangement were involved. The reaction offers easy availability of starting materials, wide substrate scope, high functionality tolerance, and operational simplicity.
F. Zhang, P. Du, J. Chen, H. Wang, Q. Luo, X. Wan, Org. Lett., 2014, 16, 1932-1935.
Oxidative ring expansion of methylenecyclopropanes with CAN under oxygen atmosphere was investigated. A facile conversion affording 2,2-diarylcyclobutanones occurred in good yields.
V. Nair, T. D. Suja, K. Mohanan, Synthesis, 2006, 2531-2534.
A practical and environmentally friendly method for the oxidative rearrangement of five- and six-membered cyclic tertiary allylic alcohols to α,β-unsaturated β-disubstituted ketones by IBX in DMSO is described. Several conventional protecting groups (e.g., Ac, MOM, and TBDPS) are tolerated.
M. Shibuya, S. Ito, M. Takahashi, Y. Iwabuchi, Org. Lett., 2004, 6, 4303-4306.
Pd-catalyzed enantioselective diborations of prochiral allenes followed by allylation reactions with primary imines provide vinyl boronates which may be oxidized to give nonracemic Mannich products. Alternatively, enantiomerically enriched homoallylic amine derivatives may be obtained by protonation and Suzuki cross-coupling of the vinyl boronate.
J. D. Sieber, J. P. Morken, J. Am. Chem. Soc., 2006, 128, 74-75.
An efficient method for the oxidation of an olefin to the less substituted carbonyl compound is described. This one pot conversion includes hydroboration with borane dimethyl sulfide (BDMS), followed by oxidation of the resulting alkylboranes with tetrapropylammonium perruthenate (TPAP) and NMO.
M. H. Yates, Tetrahedron Lett., 1997, 38, 2813-2816.
HTIB mediates an oxidative transposition of vinyl halides to provide α-halo ketones as useful and polyvalent synthetic precursors. Insights into the mechanism and an enantioselective transformation are reported too.
A. Jobin-Des Lauriers, C. Y. Legault, Org. Lett., 2016, 18, 108-111.
An anthraquinone-catalyzed photooxidative keto-trifluoromethylation of styrenes with the readily available Langlois reagent (CF3SO2Na) under an oxygen atmosphere proceeds smoothly to give α-trifluoromethyl ketones in good yield with good selectivity.
E. Yamaguchi, Y. Kamito, K. Matsuo, J. Ishihara, A. Itoh, Synthesis, 2018, 50, 3161-3168.
An alternative pathway to the Wacker oxidation of internal olefins involving epoxidation of trans-alkenes followed by a mild and highly regioselective isomerization gives ketone isomers in good yield.
J. R. Lamb, M. Mulzer, A. M. LaPointe, G. W. Coates, J. Am. Chem. Soc., 2015, 137, 15049-15054.