Ketones bifunctional

In real systems (hydrocarbon-02-catalyst), various oxidation products, such as alcohols, aldehydes, ketones, bifunctional compounds, are formed in the course of oxidation. Many of them readily react with ion-oxidants in oxidative reactions. Therefore, radicals are generated via several routes in the developed oxidative process, and the ratio of rates of these processes changes with the development of the process [5], The products of hydrocarbon oxidation interact with the catalyst and change the ligand sphere around the transition metal ion. This phenomenon was studied for the decomposition of sec-decyl hydroperoxide to free radicals catalyzed by cupric stearate in the presence of alcohol, ketone, and carbon acid [70-74], The addition of all these compounds was found to lower the effective rate constant of catalytic hydroperoxide decomposition. The experimental data are in agreement with the following scheme of the parallel equilibrium reactions with the formation of Cu-hydroperoxide complexes with a lower activity. 

In real systems (hydrocarbon-02-catalyst), various oxidation products, such as alcohols, aldehydes, ketones, bifunctional compounds, are formed in the course of oxidation. Many of them readily react with ion-oxidants in oxidative reactions. Therefore, radicals are generated via several routes in the developed oxidative process, and the ratio of rates of these processes changes with the development of the... 

Other interesting synthetic applications of the ketone-derived enamine alkylation are found in the monomethylation of steroid enamines (249), extension of the benzylation reaction (250) to a ferrocene derivative (251), the use of a-bromoesters (252) and ketones (252) or their vinylogues (25J), in the syntheses of alantolactone (254-256), isoalantolactone (257), and with a bridged bis-enamine (258). The use of bifunctional alkylating agents is also seen in the introduction of an acetylenic substituent in the synthesis of the characteristic fragrant constituent of jasmine (259), the synthesis of macrocyclic ketolactones (260), the use of butyrolactone (261), and the intermolecular or intramolecular double alkylations of enamines with dihalides (262). 

Tlie bifunctional sulfenyl chloride 213 was obtained by chlorination of 144 in good yield, although excessive chlorination led to the saturated compound 214 (94CB533). A series of compounds 215-220 were obtained from 213 by reactions with secondary amines ferf-butyl methyl ketone hexane-2,4-dione 2,6-dimethylcyclohexanone diethyl malonate and acetylacetone, respectively. 

A palladium-catalyzed one-step synthesis of dihydrobenzo[fc]furan-based fused aromatic heterocycles from bifunctional bromoenoates or bromoalkyl indoles and iodoarenes was reported, and an example is provided in the scheme below <060L3601>. 2-Alkyl- or 2-aryl-substituted benzo[ >]furans were synthesized by a copper-TMEDA catalyzed intramolecular annulation from the corresponding ketones <06OL1467>. 

Our work on the bifunctional activation of CO insertion was prompted by the thought that strong molecular Lewis acids should be more effective and more general than simple cations. It already had been observed that molecular Lewis acids would promote a molecular Fischer-Tropsch type reaction (5), and that iron diene complexes can be converted to polycyclic ketones by the action of aluminum halides, equation 7,(18), but information on the course of these reactions was sketchy. 

The 1,3-dipolar addition to terminal alkenes of nitrile oxides, generated from nitromethylene derivatives of bicycloheptane, provides 9,ll-ethano-13,15-isoxazolinoprostanoids, PGH analogs, with alkyl, phenyl, or additional heterocyclic fragment in the oo-chain (461). Chemical transformations of 9,11-ethano-13,15-isoxazolinoprostanoids furnish prostanoids with bifunctional fragments of P-hydroxyketone and a-aminoalcohol in the oo-chain. The reaction of P-hydroxy ketones with methanesulfonyl chloride gives rise to prostanoids with an enone component in the oo-chain. 9,ll-Ethano-16-thiaprostanoids have been prepared, for the first time, by nucleophilic addition of thiols to the polarized double bond in the oo-chain. The 1,3-dipolar addition to terminal alkenes of nitrile oxides, generated from nitromethylene derivatives of bicycloheptane provides 9,ll-ethano-13,15-isoxazolinoprostanoids with an alkyl, phenyl, or additional heterocyclic fragment in the oo-chain (462). 

The concerted delivery of protons from OH and hydride from RuH found in these Shvo systems is related to the proposed mechanism of hydrogenation of ketones (Scheme 7.15) by a series of ruthenium systems that operate by metal-ligand bifunctional catalysis [86]. A series of Ru complexes reported by Noyori, Ohkuma and coworkers exhibit extraordinary reactivity in the enantioselective hydrogenation of ketones. These systems are described in detail in Chapters 20 and 31, and mechanistic issues of these hydrogenations by ruthenium complexes have been reviewed [87]. 

Choudary, B.M. Kantam, M.L. Ranganath, K.V.S. Mahendar, K. Sreedhar, B. Bifunctional nanocrystalline MgO for chiral epoxy ketones via Claisen-Schmidt condensation-asymmetric epoxi-dation reactions. J. Am. Chem. Soc. 2004,126, 3396-3397. 

One of the systems was found to be very efficient catalyzing enantioface-selective hydrogen transfer reactions to aromatic and in particular to aliphatic ketones with up to 95% ee. Regarding the latter reaction these are unprecedented ee values. The reaction mechanism of these transformations is best described as a metal-ligand bifunctional catalysis passing through a pericyclic-like transition state. 

One-Pot Multistep Synthesis of Ketones on Bifunctional Zeolite Catalysts. One-pot multistep reactions constitute an elegant and efficient way to decrease the number of chemical and separation steps, hence, to develop greener synthesis processes. Bifunctional metal-acidic or metal-basic zeolite catalysts, which can be prepared easily with the desired properties (e.g., distribution of the... 

Simple reactivity inversion" implies using an umpoled synthon whose origin has, in principle, nothing in common with the synthon with "unnatural" polarity. An example of this type of reactivity inversion is found in one of the possible synthesis of cw-jasmone (3) in which the nitroethane (4) is used as an equivalent of an "acetyl anion" and reacts with an a,P-unsaturated ketone to give the corresponding 1,4-bifunctional system which can then be transformed by a Nef-type reaction into the dissonant 1,4-dicarbonyl system [5]. An intramolecular aldol condensation finally affords the target molecule (Scheme 5.3). 

In contrast, the so-called bis-nor-Wieland-Miescher ketone (2) is a more complex synthetic problem, since the molecule is a multidissonant system with two dissonant bifunctional group relationships (1,4-D and 1,6-D) and two dissonant cyclopentane rings, besides a 1,5-consonant bifunctional group relationship. Its synthesis was only accomplished 30 years after the synthesis of its consonant homologue [5],... 

The dimerization of functional alkenes such as acrylates and acrylonitrile represents an attractive route to obtain bifunctional compounds such as dicarboxylates and diamine, respectively. The head-to-tail dimerizahon of acrylates and vinyl ketones was catalyzed by an iridium hydride complex generated in situ from [IrCl(cod)]2 and alcohols in the presence of P(OMe)3 and Na2C03 [26]. The reaction of butyl acrylate 51 in the presence of [IrCl(cod)]2 in 1-butanol led to a head-to-tail dimer, 2-methyl-2-pentenedioic acid dibutyl ester (53%), along with butyl propionate (35%) which is formed by hydrogen transfer from 1-butanol. In order to avoid... 

Trost s group reported direct catalytic enantioselective aldol reaction of unmodified ketones using dinuclear Zn complex 21 [Eq. (13.10)]. This reaction is noteworthy because products from linear aliphatic aldehydes were also obtained in reasonable chemical yields and enantioselectivity, in addition to secondary and tertiary alkyl-substituted aldehydes. Primary alkyl-substituted aldehydes are normally problematic substrates for direct aldol reaction because self-aldol condensation of the aldehydes complicates the reaction. Bifunctional Zn catalysis 22 was proposed, in which one Zn atom acts as a Lewis acid to activate an aldehyde and the other Zn-alkoxide acts as a Bronsted base to generate a Zn-enolate. The... 

Okamura and Nakatani [65] revealed that the cycloaddition of 3-hydroxy-2-py-rone 107 with electron deficient dienophiles such as simple a,p-unsaturated aldehydes form the endo adduct under base catalysis. The reaction proceeds under NEtj, but demonstrates superior selectivity with Cinchona alkaloids. More recently, Deng et al. [66], through use of modified Cinchona alkaloids, expanded the dienophile pool in the Diels-Alder reaction of 3-hydroxy-2-pyrone 107 with a,p-unsaturated ketones. The mechanistic insight reveals that the bifunctional Cinchona alkaloid catalyst, via multiple hydrogen bonding, raises the HOMO of the 2-pyrone while lowering the LUMO of the dienophile with simultaneous stereocontrol over the substrates (Scheme 22). 

In related work, Sasai developed several bifunctional BINOL-derived catalysts for the aza-Morita-Baylis-Hillman (aza-MBH) reaction [111]. In early studies, careful optimization of the catalyst structure regarding the location of the Lewis base unit revealed 41 as an optimal catalyst for the aza-MBH reaction between acyclic a,P-unsaturated ketones and N-tosyl imines. Systematic protection or modification of each basic and acidic moiety of 41 revealed that all four heterofunctionalities were necessary to maintain both chemical and optical yields. As seen in Scheme 5.58, MO calculations suggest that one hydroxyl groups forms a... 

The same group reported that bifunctional thiourea 12 catalyzed the enantiose-lective Michael addition [149-152] of a-alkyl and also a-aryl cyanoacetates to alkyl vinyl ketones and aryl vinyl ketones, respectively, to give the desired... 

The Tsogoeva group, in 2006, reported the introduction of newly designed bifunctional secondary amine-functionalized proline-based thioureas (95 and 96) and the primary amine-functionalized thioureas (97-99) for catalysis of the asymmetric addition of ketones to trans-P-nitrostyrenes (Figure 6.30) [260, 261]. Using... 

Scheme 6.102 Bifunctional catalysis with primary amine thiourea 99 Proposed transition states to explain the onfi-diastereoselectivity (A) and the syn- diastereoselectivity (B) of the Michael addition of both acylic and cyclic ketones to frans-P-nitrostyrene.

M. Shi and Y.-L. Shi reported the synthesis and application of new bifunctional axially chiral (thio) urea-phosphine organocatalysts in the asymmetric aza-Morita-Baylis-Hillman (MBH) reaction [176, 177] of N-sulfonated imines with methyl vinyl ketone (MVK), phenyl vinyl ketone (PVK), ethyl vinyl ketone (EVK) or acrolein [316]. The design of the catalyst structure is based on axially chiral BINOL-derived phosphines [317, 318] that have already been successfully utilized as bifunctional catalysts in asymmetric aza-MBH reactions. The formal replacement of the hydrogen-bonding phenol group with a (thio)urea functionality led to catalysts 166-168 (Figure 6.51). 

---