tert-Butyl hydroperoxide, TBHP
Various aromatic, aliphatic and conjugated alcohols were transformed into the corresponding carboxylic acids and ketones in good yields with aq 70% t-BuOOH in the presence of catalytic amounts of bismuth(III) oxide. This method possesses does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under ambient conditions. The overall method is green.
P. Malik, D. Chakraborty, Synthesis, 2010, 3736-3740.
The cationic complex [(pymox-Me2)RuCl2]+BF4- is a highly effective catalyst for the C-H bond oxidation of aryl alkanes in water using tert-butyl hydroperoxide as oxidant to yield various aryl ketones at room temperature in water as solvent. A solvent-caged oxygen rebounding mechanism via a Ru(IV)-oxo intermediate species is suggested.
C. S. Yi, K.-H. Kwon, D. W. Lee, Org. Lett., 2009, 11, 1567-1569.
The bismuth and picolinic acid-catalyzed oxidation of alkyl arenes with tert-butyl hydroperoxide in pyridine and acetic acid gave benzylic ketones in good yields. Alternatively, oxidation of methyl arenes gave the corresponding substituted benzoic acids. A radical mechanism is discussed.
Y. Bonvin, E. Callens, I. Larrosa, D. A. Henderson, J. Oldham, A. J. Burton, A. G. M. Barrett, Org. Lett., 2005, 7, 4549-4552.
Copper(II) catalyzes a cross dehydrogenative coupling (CDC) reaction of aldehydes with alkylbenzenes in the presence of TBHP to yield benzylic esters.
S. K. Rout, S. Guin, K. K. Ghara, A. Banerjee, B. K. Patel, Org. Lett., 2012, 14, 3982-3985.
A highly efficient oxidation of propargylic alcohols to ynones is catalyzed by copper nanoparticles (Cu Nps) with TBHP or air as oxidants. With bipyridine as the ligand, the reaction was accelerated significantly and led in good to excellent yields to a variety of propargylic alcohols.
C. Han, M. Yu, W. Sun, Y. Yao, Synlett, 2011, 2363-2368.
Utilizing the rapidly synthesized Quinox ligand and commercially available aqueous TBHP, a Wacker-type oxidation efficiently converts even traditionally challenging substrates such as protected allylic alcohols to the corresponding oxidized products. Enantioenriched substrates undergo oxidation with complete retention of enantiomeric excess.
B. W. Michel, A. M. Camelio, C. N. Cornell, M. S. Sigman, J. Am. Chem. Soc., 2009, 131, 6076-6077.
Wacker-Type Oxidation of Internal Alkenes using Pd(Quinox) and TBHP
R. J. DeLuca, J. L. Edwards, L. D. Steffens, B. W. Michel, X. Qiao, C. Zhu, S. P. Cook, M. S. Sigman, J. Org. Chem., 2013, 78, 1682-1683.
A ruthenium-catalyzed oxidation of alkenes allows an efficient route to α-diketones using TBHP as an oxidant, is highly functional group tolerant and practically convenient, requires no additional ligand, and operates under mild conditions with short reaction times. Based upon experimental observations, a plausible mechanism is proposed.
S. Chen, Z. Liu, E. Shi, L. Chen, W. Wei, H. Li, Y. Cheng, X. Wan, Org. Lett., 2011, 13, 2274-2277.
Olefin substrates can be converted to the corresponding enones or 1,4-enediones in very good yields in short reaction times using a Cu(II) 2-quinoxalinol salen complex as the catalyst and tert-butyl hydroperoxide (TBHP) as the oxidant via allylic activation. The reaction tolerates many additional functional groups.
Y. Li, T. B. Lee, T. Tang, A. V. Gamble, A. E. V. Gorden, J. Org. Chem., 2012, 77, 4628-4633.
Dirhodium(II) caprolactamate effectively catalyzes the allylic oxidation of a variety of olefins and enones with tert-butyl hydroperoxide as terminal oxidant. The reaction is completely selective, tolerant of air and moisture, and can be performed with as little as 0.1 mol % catalyst in minutes.
A. E. Lurain, A. Maestri, A. R. Kelli, P. J. Carroll, P. J. Walsh, J. Am. Chem. Soc., 2004, 126, 13622-13623.
A new and simple method is described for the one-step oxidation of α,β-enones to 1,4-enediones in good yields using t-butylhydroperoxide as stoichiometric oxidant and 20% Pd(OH)2 on carbon as catalyst. The same reagents have been used to convert ethylene ketals of α,β-enones to the corresponding monoethylene ketals of 1,4-enediones. The mechanism is discussed.
J.-Q. Yu, E. J. Corey, J. Am. Chem. Soc., 2003, 125, 3232-3233.
A new catalytic system for the asymmetric epoxidation of allylic alcohols has been developed featuring high enantioselectivity for Z olefins, catalyst loading of less than 1 mol%, reaction temperatures of 0°C to room temperature over a shorter time, use of aqueous tert-butyl hydroperoxide (TBHP) instead of anhydrous TBHP as an achiral oxidant, and simple workup procedures for small expoxy alcohols.
W. Zhang, A. Basak, Y. Kosugi, Y. Hoshino, H. Yamamoto, Angew. Chem. Int. Ed., 2005, 44, 4389-4391.
An operationally straightforward method for the amidation of aldehydes with economic ammonium chloride or amine hydrochloride salts enables the synthesis of various amides in good yield by using inexpensive copper sulfate or copper(I) oxide as a catalyst and aqueous tert-butyl hydroperoxide as an oxidant. Chiral amines can be used without detectable racemization.
S. C. Ghosh, J. S. Y. Ngiam, A. M. Seayad, D. T. Tuan, C. L. L. Chai, A. Chen, J. Org. Chem., 2012, 77, 8007-8015.
A mild and efficient oxidative amidation of aldehydes uses amine HCl salts and tert-butyl hydroperoxide as an oxidant in the presence of a copper catalyst.
W.-J. Yoo, C.-J. Li, J. Am. Chem. Soc., 2006, 128, 13064-13065.
The catalytic asymmetric addition of alkyl groups to ketones under highly concentrated and solvent-free conditions permits reduction in catalyst loading by a factor of 2- to 40-fold compared with standard reaction conditions employing toluene and hexanes. Using cyclic conjugated enones, solvent-free asymmetric addition followed by a diastereoselective epoxidation using 5.5 M decane solution of tert-butyl hydroperoxide generated epoxy alcohols.
S.-J. Jeon, H. Li, P. J. Walsh, J. Am. Chem. Soc., 2005, 127, 16416-16425.
A catalytic asymmetric epoxidation reaction of various α,β-unsaturated esters via a conjugate addition of an oxidant using an yttirium-chiral biphenyldiol catalyst yielded the corresponding α,β-epoxy esters in up to 97% yield and 99% ee.
H. Kakei, R. Tsuji, T. Ohshima, M. Shibasaki, J. Am. Chem. Soc., 2005, 127, 8962-8963.
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.
With an easily accessible cinchona alkaloid catalyst, efficient enantioselective peroxidation and epoxidation have been successfully developed. Employing readily available α,β-unsaturated ketones and hydroperoxides, this novel reaction will open new possibilities in the asymmetric synthesis of chiral peroxides and epoxides.
X. Lu, Y. Liu, B. Sun, B. Cindric, L. Deng, J. Am. Chem. Soc., 2008, 130, 8134-8135.
Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes through Cp2ZrCl2-catalyzed methylalumination and subsequent oxygenation with peroxyzinc species and electrophilic trapping with carboxylic anydrides. The tandem carbometalation/oxygenation tolerates free and protected alcohols, heterocycles, olefins, and nitriles.
J. R. DeBergh, K. M. Spivey, J. M. Ready, J. Am. Chem. Soc., 2008, 130, 7828-7829.
Nitroarenes react with anions of tert-butyl and cumyl hydroperoxides in the presence of strong bases to form substituted o- and p-nitrophenols. The reaction usually proceeds in high yields and is of practical value as a method of synthesis and manufacturing of nitrophenols.
M. Makosza, K. Sienkiewicz, J. Org. Chem., 1998, 63, 4199-4208.
A simple and effective copper-catalyzed oxidative cross-coupling of dimethylanilines with alkynes in the presence of tert-BuOOH allows the construction of propargylamines via a combination of sp3 C-H bond and sp C-H bond activations followed by C-C bond formation.
Z. Li, C.-J. Li, J. Am. Chem. Soc., 2004, 126, 11810-11811.
A copper-catalyzed amidation of allylic and benzylic C-H is applicable to the coupling of a diverse set of hydrocarbon species with aryl, heteroaryl, and alkyl sulfonamides and is tolerant of a variety of functional groups.
G. Pelletier, D. A. Powell, Org. Lett., 2006, 8, 6031-6034.
NaI-catalyzed direct condensation of sulfonamides and formamides enables N-sulfonyl formamidine synthesis without hazardous reagents or transition-metal catalysts. The green methodology features high atom economy, operational simplicity, and good tolerance with diverse functional groups.
S. Chen, Y. Xu, X. Wan, Org. Lett., 2011, 13, 6152-6155.
Cu(OAc)2-promoted TBHP oxidative coupling reaction of formamides with thiophenols gives S-aryl dialkyl thiocarbamates in high yield under solvent-free conditions through direct C-H bond activation of formamides.
Y.-q. Yuan, S.-r. Guo, J.-n. Xiang, Synlett, 2013, 24, 443-448.
An iron-catalyzed route for the regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from the reaction of diarylhydrazones and vicinal diols allows the conversions of a broad range of substrates.
N. Panda, A. K. Jena, J. Org. Chem., 2012, 77, 9401-9406.
A facile one-pot, transition-metal-free process enables the synthesis of various polysubstituted oxazoles via t-BuOOH/I2-mediated domino oxidative cyclization from readily available starting materials under mild conditions.
H. Jiang, H. Huang, H. Cao, C. Qi, Org. Lett., 2010, 12, 5561-5563.
In a practical and simple synthesis of 2,5-disubstituted oxazoles via an iodine-catalyzed tandem oxidative cyclization, a wide range of common commercial aromatic aldehydes can be used as reaction substrates, which displayed excellent functional group compatibility.
C. Wan, L. Gao, Q. Wang, J. Zhang, Z. Wang, Org. Lett., 2010, 12, 3902-9305.
A highly efficient copper-catalyzed tandem oxidative cyclization gives polysubstituted oxazoles from readily available starting materials under mild conditions. This is an attractive alternative method for the synthesis of oxazole derivatives.
C. Wang, J. Zhang, S. Wang, J. Fan, Z. Wang, Org. Lett., 2010, 12, 2338-2341.
A metal-free sequential dual oxidative amination of C(sp3)-H bonds under ambient conditions affords imidazo[1,5-a]pyridines in very good yields. The reaction involves two oxidative C-N couplings and one oxidative dehydrogenation process with six hydrogen atoms removed.
Y. Yan, Y. Zhang, Z. Zha, Z. Wang, Org. Lett., 2013, 15, 2274-2277.
A facile approach allows the synthesis of 2-phenylquinazolines via a tandem reaction following sp3 C-H functionalization. Twenty-five examples of 2-phenylquinazolines were obtained from easily available 2-aminobenzophenones and benzylic amines with good to excellent yields.
J. Zhang, D. Zhu, C. Yu, C. Wan, Z. Wang, Org. Lett., 2010, 12, 2841-2843.
A facile and efficient method for the synthesis of 2-phenylquinazolines from 2-aminobenzophenones and benzylamines us catalyzed by ceric ammonium nitrate (CAN)-TBHP in acetonitrile. The corresponding 2-phenylquinazolines were obtained in good to excellent yields.
K. Karnakar, J. Shangkar, S. N. Murthy, K. Ramesch, Y. V. D. Nageshwar, Synlett, 2011, 1089-1096.
A facile metal-free oxidative amination of benzoxazole by activation of C-H bonds with secondary or primary amines in the presence of catalytic iodine in aqueous tert-butyl hydroperoxide proceeds smoothly at ambient temperature under neat reaction condition to furnish products in high yields. This user-friendly method produces only tertiary butanol and water as byproducts.
M. Lamani, K. R. Prabhu, J. Org. Chem., 2011, 76, 7938-7944.
Catalytic amounts of tetrabutylammoniumiodide (TBAI), aqueous solutions of H2O2 or TBHP as co-oxidant enabled an efficient transition-metal-free amination of benzoxazoles under mild reaction conditions, to yield highly desirable 2-aminobenzoxazoles in good yields. First mechanistic experiments indicate the in situ iodination of the secondary amine as the putative mode of activation.
T. Froehr, C. P. Sindlinger, U. Kloeckner, P. Finkbeiner, B. J. Nachtsheim, Org. Lett., 2011, 13, 3754-3757.
Cu-catalyzed sp3 C-H bond activation α to the nitrogen atom of o-alkynylated N,N-dimethylamines followed by an intramolecular nucleophilic attack with the alkyne, using an aqueous solution of tert-butyl hydroperoxide (TBHP) as the oxidant, enables a tandem catalytic synthesis of 3-aroylindoles. In this synthesis, both C-C and C-O bonds are installed at the expense of two sp3 C-H bond cleavages.
A. Gogoi, S. Guin, S. K. Rout, B. K. Patel, Org. Lett., 2013, 15, 1802-1805.
Aqueous tert-butyl hydroperoxide (70%) is an inexpensive reagent for the regioselective and chemoselective deprotection of terminal acetonide groups. Various acetonide derivatives furnish the corresponding deprotected diols in good yields, while a large number of acid labile protecting functional groups and other functional moieties were found to be unaffected under the conditions.
M. R. Maddani, K. R. Prabhu, Synlett, 2011, 821-825.
A mild and practical protocol for the copper-mediated trifluoromethylation of aryl and heteroaryl boronic acids using NaSO2CF3 (Langlois’ reagent) and TBHP proceeds at room temperature under ambient conditions. The products can be readily purified by extraction or column chromatography.
Y. Ye, S. A. Künzi, M. S. Sanford, Org. Lett., 2012, 14, 4979-7981.
A copper-catalyzed decarboxylative trifluoromethylation of various α,β-unsaturated carboxylic acids was achieved by using a stable and inexpensive solid, sodium trifluoromethanesulfinate (CF3SO2Na, Langlois reagent). In addition, an iron-catalysis enables a difluoromethylation of aryl-substituted acrylic acids by using zinc difluoromethanesulfinate (DFMS, (CF2HSO2)2Zn, Baran reagent) via a similar radical process.
Z. Li, Z. Cui, Z.-Q. Liu, Org. Lett., 2013, 15, 406-409.