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Cyclobutanols undergo ring expansion with molecular oxygen in the presence of Co(acac)2 to afford 1,2-dioxane-hemiperoxyketals. In the course of acylation, we observed that endoperoxides rearranged into ?-lactone in the presence of triethylamine. Thus, a generalization of this ring contraction through a Kornblum DeLaMare rearrangement is here reported. Application of this transformation to monosubstituted 1,2-dioxane derivatives also led to 1,4-ketoaldehydes, in proportions depending on the nature of the substituent. These same conditions applied to five-membered dioxolane analogues led to fragmentation instead, through a retro-aldol type process. This study emphasizes the difference of stability of 1,2-dioxane and 1,2-dioxolane against organic bases, 1,2-dioxolanes having proved to be particularly reactive whereas 1,2-dioxanes showed a relative tolerance under these conditions.

Described are methods for preparing a deuterated aldehyde using with a photocatalyst and a hydrogen atom transfer agent in a H2O free solvent comprising D2O and an organic solvent under an inert gas. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions.

A new dibrominated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is reported as a new metal-free photocatalyst. This BODIPY showed similar optoelectronic, electrochemical, and performance properties to those of Ru(bpy)3Cl2, one of the most common photocatalysts in a known radical-ionic transformation, such as the formation of 1,4-dicarbonyl compounds. Moreover, additional sequences in which the generated oxonium ion is trapped by an internal nucleophile were developed using this BODIPY photocatalyst. These new sequences allowed the straightforward preparation of ?3-alkoxylactones, monoprotected 1,4-ketoaldehydes, and dihydrofurans. This new catalyst, the methodology, and the forged functional groups could be important tools in organic synthesis.

A transformation of fluxional into configurationally stable axially chiral N-arylpyrroles was achieved with a highly atroposelective electrophilic aromatic substitution catalyzed by a chiral-at-metal rhodium Lewis acid. Specifically, N-arylpyrroles were alkylated with N-acryloyl-1H-pyrazole electrophiles in up to 93 percent yield and with up to >99.5 percent ee, and follow-up conversions reveal the synthetic utility of this new method. DFT calculations elucidate the origins of the observed excellent atroposelectivity.

A sequential multicomponent synthesis of highly substituted pyrrole-3-carboxaldehydes has been developed under metal-free conditions. This one-pot protocol involves proline-catalyzed direct chemoselective Mannich reaction-cyclization between 1,4-ketoaldehyde and in situ generated Ar/HetAr-imines followed by aerobic oxidative-aromatization at room temperature. A series of fully substituted pyrrole-3-carboxaldehydes and other diverse fused heterocycles have been synthesized. These compounds were tested for in vitro antibacterial and antifungal activities, and the selected ones display significant activity against the tested bacterial strains with a MIC value of 16 μg mL-1, which is close to that of the standard drug chloramphenicol. The bioactivity outcome was further analyzed using docking studies.

A mild and green photo-organocatalytic protocol for the highly efficient acetalization of aldehydes has been developed. Utilizing thioxanthenone as the photocatalyst and inexpensive household lamps as the light source, a variety of aromatic and aliphatic aldehydes have been converted into acyclic and cyclic acetals in high yields. The reaction mechanism was extensively studied.

A Ru2+-photocatalyzed, visible-light-mediated ATRA reaction for the straightforward preparation of 1,4-ketoaldehydes, 1,4-diketones, and 1,4-ketoesters, which are of difficult access by other means, is reported herein. This method employs readily accessible α-bromoketones and alkyl vinyl ethers as starting materials, allowing the construction of secondary, tertiary, and challenging quaternary centers. In addition, the synthetic usefulness of this method is illustrated by applying it to the construction of substituted pyrroles.

A facile visible-light photocatalytic conjugate addition to prepare 1,4-dicarbonyl compounds has been developed by employing readily available aroyl chlorides as aryl radical sources. This operationally simple method shows a broad scope with regard to both aroyl chlorides and Michael acceptors. As a result, a variety of 1,4-diketones were efficiently synthesized in moderate to good yields.

We have investigated the continuous flow photooxidation of several conjugated dienes and subsequent rearrangement using a practical and safe continuous-flow homemade engineered setup. End-to-end approaches involving endoperoxidation, Kornblum-DeLaMare rearrangement, and additional rearrangements are comprehensively detailed with optimization, scope, and scale-up to obtain useful hydroxyenones, furans, and 1,4-dicarbonyl building blocks.

An organocatalytic redox isomerization strategy has been developed for the synthesis of 1,4-ketoaldehydes. DABCO was found to be the best catalyst for the isomerization of -hydroxy enones. With 20 mol % of DABCO as catalyst and DMSO as the solvent high yi

A new carboxylic acid reductase (CAR) gene from Segniliparus rotundus DSM 44985 was overexpressed in Escherichia coli. The recombinant enzyme exhibited high activity toward a variety of aromatic and aliphatic carboxylic acids. Especially, it effectively reduced 4-hydroxybenzoic acid (8a) and 4-nitrobenzoic acid (19a), toward which the known Nocardia CAR exhibited no or little activity. The recombinant E. coli cells co-expressing the Segniliparus CAR and Nocardia PPTase genes catalyzed the reductions of vanillic acid (20a) and 3,4-dihydroxyphenylacetic acid (25a) to give vanillyl alcohol (20c) and 3-hydroxytyrosol (25c) with high yield, respectively. The endogenous aldehyde reductases of E. coli should be responsible for the further reduction of the produced aldehydes. These results demonstrated that Segniliparus CAR was a useful addition to the biocatalyst tool-box for the reduction of carboxylic acids and might find applications in the synthesis of valuable bio-based chemicals from renewable resources.

Unsaturated CC double bonds with a phenyl substituent can be cleaved with iodylbenzene and iodosylbenzene to give carbonyl compounds. It is believed that the reactions occur via a radical pathway. The allylic oxidation of cyclic alkenes lacking a phenyl substituent was achieved in acetonitrile/water mixture (3:1) also using iodylbenzene and iodosylbenzene.

Photolysis of γ-azidobutyrophenone derivatives yields 1,4 ketyl biradicals via intramolecular H-atom abstraction. The 1,4 ketyl biradicals expel a nitrogen molecule to form 1,5 ketyl iminyl biradicals, which decay by ring closure to form a new carbon-nitr

Stereoselectivity for (5-phenyltetrahydrofur-2-yl)alkan-1-ol formation (cis:trans 1:99) from 5-methyl- and 5-phenyl-substituted 1-phenylpent-4-en-1-ols via cobalt-catalyzed aerobic oxidation was independent of the olefinic π-bond configuration of the su

Based on the analysis of the mechanism of aerobic oxidation of alcohols using Ru(NO)-salen catalyst, we designed a new complex, Ru(PPh3)(OH)-salen 3, which was proved to be an excellent catalyst for chemoselective aerobic oxidation of primary alcohols to the aldehydes in the presence of secondary alcohols under ambient and non-irradiated conditions. Complex 3 was also successfully applied to the oxidation of 1-phenyl-1,n-diols to the lactols or the n-hydroxy aldehyde. It is of note that selective oxidation of primary alcohols was achieved even in the presence of activated secondary alcohols.

(Chemical Equation Presented) 1,4-Disubstituted 2,3-dioxabicyclo[2.2.2]oct- 5-enes were dihydroxylated with osmium tetroxide to yield diols anti to the peroxide linkage in a highly selective manner. Reduction of the peroxide bond furnished cyclohexane-1,2,3,4-tetraols with toxocarol relative stereochemistry in excellent yield. This new methodology was employed to synthesize the natural product (1S,2R,3S,4R,5R)-2-methyl-5-(propan-2-yl)cyclohexane-1,2,3,4-tetrol (1) in a short sequence from (R)-α-phellandrene. Moreover, during the study of the chemistry of 2,3-dioxabicyclo[2.2.2]octane-5,6-diols a hitherto unknown rearrangement was discovered which has wide applicability for the synthesis of 1,4-dicarbonyls, including optically enriched synthons. A broad range of mechanistic investigations applicable to this rearrangement are also reported.

N,N-Diphenylguanidinium ion associated with the noncoordinating BArF counterion is shown to be an effective catalyst for the [3,3]-sigmatropic rearrangement of a variety of substituted allyl vinyl ethers. Highly enantioselective catalytic Claisen rearrangements of ester-substituted allyl vinyl ethers are then documented using a new C2-symmetric guanidinium ion derivative. Copyright

Bishomoallylic alcohols (pent-4-en-1-ols) underwent efficient oxidative cyclizations, if treated with O2 and bis{2,2,2-trifluoromethyl-1- [(1R,4S)-1,7,7-trimethyl-2-(oxo-κO)bicyclo[2.2.1]hept-3-yliden] ethanolato-κO}cobalt(ii) in solutions of 2-propanol at 60 °C. Ring closures occurred diastereoselectively and afforded 2,3-trans- (96% de), 2,4-cis- (～60% de), and 2,5-trans-substituted (>99% de) (phenyl)tetrahydrofur-2-ylmethanols as major components. Formation of bicyclic compounds and a 2,3,4,5-substituted oxolane was feasible as exemplified by syntheses of oxabicyclo[4.3.0]nonylmethanols and a derivative of natural product magnosalicin in 61-72% (90-99% de). The effectiveness of tetrahydrofuran synthesis was critically dependent on (i) solvent, (ii) reaction temperature, (iii) initial cobalt concentration, (iv) chain length between hydroxyl and vinyl groups, and (v) substitution at reacting entities. A sequence is proposed for rationalizing observed selectivities.

1,4-Alkynediols serve as readily available starting materials for isomerisation to 1,4-diketones, which can be converted in situ into the corresponding furans by acid-catalysed dehydration. A range of 2,5-disubstituted furans was prepared using the ruthenium-based catalyst Ru(PPh3)3(CO)H2 with Xantphos at 1 mol % loading.

Pd-catalyzed carboetherifications of 1-, 2-, or 3-substituted γ-hydroxy internal alkenes afford tetrahydrofuran products bearing three stereocenters in good yield with moderate to good stereoselectivity.

A range of 3-aroyl-propionic acids have been cyclised to unsaturated lactones which, upon reduction using DIBAL-H and reaction with an ammonia source, gave 2-arylpyrroles (Ar = Ph, 1-naphthyl, o-phenoxyphenyl and 4-methyl-2-methylsulfanylphenyl) in excellent yields. Reaction of 2,6-disubstituted aroylpropanals (Ar = 2,4,6-Me3C6H2, anthracenyl and 2-Me-naphthalen-1-yl) with an ammonia source failed to generate pyrroles. The arylpyrroles react readily with ketones or aldehydes in ethanol or under eutectic mix melt conditions to give bis-(pyrrolyl)methanes in excellent isolated yields.

Aldehydes were obtained in excellent yields from ruthenium-porphyrin-catalyzed oxidation of various terminal alkenes with 2,6-dichloropyridine N-oxide under mild conditions. The aldehydes generated from these ruthenium-catalyzed alkene oxidation reactions can be used in-situ for olefination reactions with ethyl diazoacetate in the presence of PPh3, leading to one-pot diazoacetate olefination starting from alkenes.

In order to study the structure-activity relationship of anti-malarial spongean peroxides, several analogues concerning with the 6-methoxyacetyl moiety and the 3-pentyl residue in methyl 2-(3-methoxy-3-pentyl-1,2-dioxan-6-yl) acetate were synthesized and evaluated for anti-malarial activity. In order to study the structure-activity relationship of anti-malarial spongean peroxides, several analogues concerning with the 6-methoxyacetyl moiety and the 3-pentyl residue in methyl 2-(3-methoxy-3-pentyl-1,2-dioxan-6-yl)acetate were synthesized and evaluated for anti-malarial activity. The tert-butyl ester analogue 14 showed stability in mouse serum and a high selectivity index against the malaria parasite, Plasmodium falciparum, and the citronellyl analogue 31 exhibited the strongest in vitro anti-malarial activity among them, and the imidazole analogue 25 showed desirable in vivo anti-malarial activity against P. berghei infected mice.

Aldehydes in excellent yields were obtained from the ruthenium-porphyrin- catalyzed oxidation of various terminal alkenes with 2,6-dichloropyridine N-oxide under mild conditions. The aldehydes generated from these ruthenium-catalyzed alkene oxidations can be used in situ for olefination reactions with ethyl diazoacetate in the presence of PPh3 in a one-pot diazoacetate olefination starting from alkenes (see example).

N-Phenyl-substituted pyrrolidines and piperidines have been synthesized by catalytic reduction of nitrobenzene in the presence of 4- and 5-oxoaldehydes, respectively. The process involves reduction of the aromatic nitro group to give the N-phenylhydroxylamine or aniline followed by reductive amination with the two carbonyl functional groups. Monocyclic systems are generally formed in high yield and are easily purified. The method has also been extended to the synthesis of fused N-phenylazabicyclics from 2-(3-oxopropyl)cycloalkanones. A high degree of diastereoselectivity for the trans-fused product is observed in substrates having an ester group α to the cycloalkanone carbonyl. Bicyclic precursors lacking this ester group give mixtures of cis and trans products. Finally, contrary to previous reports, we have demonstrated that aniline can be substituted for nitrobenzene in these reactions.

This invention is directed towards novel alkylamide derivatives as bradykinin receptor antagonists useful for the treatment of bradykinin modulated disorders such as pain, inflammation, asthma and allergy. Furthermore, the present invention is directed to novel alkylamide derivatives as bradykinin receptor agonists useful for the treatment of bradykinin modulated disorders such as hypertension and the like.

A variety of carboxylic acids can be directly hydrogenated into the corresponding aldehydes in high yields by using homogeneous catalysts such as [Pd(PPh3)4] or combination of Pd(OAc)2 with tertiary phosphines in the presence of an excess amount of 2,2-dimethylpropionic anhydride (pivalic anhydride). As a typical example, octanoic acid can be convened into octanal in 99% yield in 3 h at 80 °C under 3.0 MPa of H2 in acetone in the presence of pivalic anhydride and a catalyst system composed of Pd(OAc)2 + 5P(p-tol)3. Such hydrogenation is widely applicable to various aliphatic, aromatic, and heterocyclic carboxylic acids as well as to di- and tribasic carboxylic acids. The process allows the presence of other functional groups such as ketonic carbonyl, nitrile, and ester groups and even internal C=C bonds. Heterogeneous palladium catalyst such as palladium on carbon also showed some catalytic activities.

A new chemical transformation for the construction of diversely functionalized cyclopropanes utilizing 1,2-dioxines and stabilized phosphorus ylides as the key precursors is presented. Through a series of mechanistic studies we have elucidated a clear understanding of the hitherto unknown complex relationship between 1,2-dioxines 1a-e, and their isomeric cis/trans γ-hydroxy enones (23 and 21a-e), cis/trans hemiacetals 24a-e, and β-ketoepoxides (e.g., 26), and how these precursors can be utilized to construct diversely functionalized cyclopropanes. Furthermore, several new synthetically useful routes to these structural isomers are presented. Key features of the cyclopropanation include the ylide acting as a mild base inducing the ring opening of the 1,2-dioxines to their isomeric cis γ-hydroxy enones 23a-e, followed by Michael addition of the ylide to the cis γ-hydroxy enones 23a-e and attachment of the electrophilic phosphorus pole of the ylide to the hydroxyl moiety, affording the intermediate 1-2λ5-oxaphospholanes 4 and setting up the observed cis stereochemistry between H1 and H3. Cyclization of the resultant enolate (30a or 30b), expulsion of triphenylphosphine oxide, and proton transfer from the reaction manifold affords the observed cyclopropanes in excellent diastereomeric excess. The utilization of Co(SALEN)2 in a catalytic manner also allows for a dramatic acceleration of reaction rates when entering the reaction manifold from the 1,2-dioxines. While cyclopropanation is favored by the use of ester-stabilized ylides, the use of keto- or aldo-stabilized ylides results in a preference for 1,4-dicarbonyl formation through a competing Kornblum-De La Mare rearrangement of the intermediate hemiacetals. This finding can be attributed to subtle differences in ylide basicity/nucleophilicity. In addition, the use of doubly substituted ester ylides allows for the incorporation of another stereogenic center within the side chain. Finally, our studies have revealed that the isomeric trans γ-hydroxy enones and the β-keto epoxides are not involved in the cyclopropanation process; however, they do represent an alternative entry point into this reaction manifold.

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In order to determine whether the remote asymmetric induction in the reduction of compounds such as 1 and 2 using borane is really controlled by intramolecular chelates of type 3, rather than dioxaborolane oxygenborane chelates of type 12, a study was undertaken to examine related reductions involving the corresponding homochiral acetal 30 and comparative reductions of the dioxaborolane 14 and the acetal 23b.While this study showed that reductions of the dioxaborolane 14 and the acetal 23b with borane and L-Selectride were virtually identical, this result did not necessarily indicate that dioxaborolane oxygens or acetal oxygens were directing borane reduction.However, that the more likely explanation for the remote asymmetric induction observed for 1 and 2 being mediated by complex 3 was confirmed by the fact that the acetal 30 gave no asymmetric induction with borane.A crystal structure of the phenylboronate ester 10 has been carried out.

Optically active γ-hydroxy ketones and aromatic hydroxy ketones with high (up to 96percent) enantiomeric excesses have been synthesized by the chemo- and enantio-selective addition of dialkylzincs to γ-keto aldehydes and aromatic keto aldehydes, respectively, using N,N-dibutylnorephedrine (DBNE) 1 and (1-methylpyrrolidin-2-yl)diphenylmethanol (DPMPM) 5 as chiral catalysts.The method provides a non-homoaldol approach to optically active γ-hydroxy ketones.

Acyl-substituted methyl radicals (RCOCH2.; R = H, Me, Ph), generated by photolysis of RCOCH2HgCl, add to alkenes, enol ethers, or vinyl sulfides to give adduct radicals that are readily trapped by PhSSPh to yield a three-component condensation product.The presence of an alkali metal carbonate is crucial in preventing side reactions resulting in the conversion of the mercurial to RCOCH3 by PhSH formed in the photolysis.

Lewis acids are employed as catalysts in the annulation of 1,4- and 1,5-dicarbonyl dielectrophiles with bis(trimethylsilyl) end ethers of β-diketones and β-keto esters. A variety of 2-(alkoxycarbonyl)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regiocontrol is observed, and good to excellent stereochemical control can be achieved at virtually every position on the new carbocycles. Intramolecular neighboring group participation is proposed to explain the unusually high selectivities attained in the annulation reaction.

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Although, α-ethoxycrotyltributyltin can be used as an equivalent of the homoenolate anion CH3-CHCH2CHO in reactions with acyl chlorides, the non-substituted α-ethoxyallyltributyltin could not be employed in this way. γ-Methoxyvinyltins, easily prepared by hydrostannation of propargylic ethers, are successfully employed as synthetic equivalents of the homoenolate anions -CH2CH2CHO and -CH2CH2COCH3 in reactions with acyl chlorides.A silylated γ-methoxyvinyltin, which is both a vinyltin and an allylsilane, reacts with acyl chlorides and aryl bromides as a promising equivalent of the homoenolate anion -CH2CH2CHO and tolerates a wide range of other reactive functional groups.

Methyl benzoate and other simple arenecarboxylic acid esters have been found to undergo 2 + 2 photochemical cycloaddition at the carbonyl group to furans and certain 1,3-dienes.These additions afford mixtures of oxetanes and their 2 + 2 cycloreversion products: 4-aryl-4-alkoxy-1,3-butadienyl formates and acetates (from furan oxetanes) and dienyl aldehydes and ketones (from cyclic 1,3-dienes).

A new three-step synthesis in good overall yield of 1,4-ketoaldehydes and 1,4-diketones is described.The method involves two sequential coupling reaction of reagents with S-phenyl carbonochloridothioate in the presence of nickel(II) or iron(III) complexes as catalysts.Application of this reaction to the synthesis of Z-jasmone and dihydrojasmone is also described.

Two short and efficient synthetic approaches for -mostly unknown- 2-arylpyrroles are presented.The key intermediates 3 are conveniently obtained from commercially available acetophenones 5 (method I) or benzoic acid derivatives 10, 11 (method II).

An efficient synthesis of 2-substituted cyclopentenones is reported.Key reactions are the cyclopropanation of 2,2-dimethyl-3(2H)-furanone and subsequent conversion to the title compounds by oxidative fragmentation.

On dye-sensitized photooxydation of 1-phenylcyclobutene the formation of 3-benzoylpropanal and 2-phenyl-3-hydroperoxycyclobutene was ascribed to oxidation with singlet oxygen, whereas a reactive oxygen species other than singlet oxygen was responsible for the formation of 1-(2-hydroxyphenyl)cyclopropanecarbaldehyde.Some attempts to explore the latter oxygen species were made.

A novel method was developed for degradation of carboxylic acid into aldehydes containing one C atom less whose key step consists in α-acetoxylation of 5-alkyl-3-methylthio-1,4-diphenyl-1,2,4-triazolium iodides by (diacetoxyiodo)benzene.The mechanism of the regioselective α-acetoxylation was studied and the diacetoxy-iodate(1)anion was shown to be the actual oxidising agent.Further oxidation reactions of tetraethylammonium diacetoxyiodate(1) were investigated.A novel method was developed for the oxidation of primary alkyl amines into aldehydes by the novel heterocyclic reagent 5-bromo-3-methylthio-1,4-diphenyl-1,2,4-triazolium bromide and diethyl azodicarboxylate.

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