Synthesis of ketones by cleavage of alkenes
The OsO4-catalyzed direct oxidation of olefins via the carbon-carbon cleavage of an osmate ester by the action of oxone allows the preparation of ketones or carboxylic acids in high yields. This method should be applicable as an alternative to ozonolysis.
B. R. Travis, R. S. Narayan, B. Borhan, J. Am. Chem. Soc., 2002, 124, 3824-3825.
N-hydroxyphthalimide (NHPI) catalyzes a metal-free, aerobic oxidative cleavage of olefins. This methodology avoids the use of toxic metals or overstoichiometric amounts of traditional oxidants, showing good economical and environmental advantages. Based on the experimental observations, a plausible mechanism is proposed.
R. Lin, F. Chen, N. Jiao, Org. Lett., 2012, 14, 4158-4161.
A mild and operationally simple protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2. The method cleaves α- and β-substituted styrenes to afford benzaldehydes and aromatic ketones in high yields with excellent chemoselectivity and very good functional group tolerance.
A. Gonzalez-de-Castro, J. Xiao, J. Am. Chem. Soc., 2015, 137, 8206-8218.
In a 2,2-azobis(isobutyronitrile)-catalyzed oxidative cleavage of gem-disubstituted alkenes with molecular oxygen as the oxidant, carbonyl compounds were obtained as the desired products in high yield under mild conditions.
G.-Z. Wang, X.-L. Li, J.-J. Dai, H.-J. Xu, J. Org. Chem., 2014, 79, 7220-7225.
A gold(I)-catalyzed oxidative cleavage of alkenes with tert-butyl hydrogenperoxide (TBHP) as the oxidant in the presence of neocuproine afforded ketones or aldehydes as products.
D. Xing, B. Guan, G. Cai, Z. Fang, L. Yang, Z. Shi, Org. Lett., 2006, 8, 693-696.
Specific oxidation protocols have been developed for the cleavage of styrenes, aliphatic olefins, and terminal aliphatic olefins to carbonyl compounds with ruthenium trichloride as catalyst. Olefins that are not fully substituted are converted to aldehydes rather than carboxylic acids.
D. Yang, C. Zhang, J. Org. Chem., 2001, 66, 4814-4818.
A catalytic amount of a composite material, RuO2/BaTi4O9, in combination with NaIO4 in EtOAc-H2O has been shown to efficiently cleave alkenes, affording ketones, aldehydes and/or carboxylic acids in high yields.
H. Okumoto, K. Ohtsuko, S. Banjoya, Synlett, 2007, 3201-3205.
Osmium tetroxide has been microencapsulated in a polyurea matrix. These microcapsules have been effectively used as recyclable catalysts in the dihydroxylation and the oxidative cleavage of olefins.
S. V. Ley, C. Ramarao, A.-L. Lee, N. Ostergaard, S. C. Smith, I. M. Shirley, Org. Lett., 2003, 5, 185-187.
The use of PhI(OAc)2 in dichloromethane enables a clean oxidative cleavage of 1,2-diols to aldehydes. In the presence of OsO4 as catalyst, NMO and 2,6-lutidine, olefinic bonds can be cleaved in acetone/water to yield the corresponding carbonyl compounds.
K. C. Nicolaou, V. A. Adsool, C. R. H. Hale, Org. Lett., 2010, 12, 1552-1555.
The oxidative cleavage of C=C bonds adjacent to aryl and alkyl moieties was efficiently achieved with monoacetylated bishydroperoxides. Base-mediated fragmentation of monoacetylated bishydroperoxides generates singlet molecular oxygen as active oxidant in situ. All the reactions furnished the respective carbonyl compounds in good yields at room temperature within short reaction times.
D. Azarifar, Z. Najminejad, Synlett, 2013, 24, 1377-1382.