104-53-0

Basic information

• Product Name: Phenylpropyl aldehyde
• Synonyms: TIMTEC-BB SBB006730;PHENYLPROPYL ALDEHYDE;3-Phenylpropan-1-al;Benzenepropanal;Dihydrocinnamaldehyde;Phenylpropionaldehyde;Propionaidehyde, 3-phenyl-;3-PHENYL-1-PROPANAL
• CAS NO: 104-53-0
• Molecular Formula: C₉H₁₀O
• Molecular Weight: 134.18
• EINECS: 203-211-8
• Product Categories: Aroma Chemicals;Aromatics Compounds;Aromatics
• Mol File: 104-53-0.mol
• Article Data: 1063

Chemical Properties

• Melting Point: -42 °C
• Boiling Point: 97-98 °C12 mm Hg(lit.)
• Flash Point: 203 °F
• Appearance: Clear colorless to light yellow/Liquid
• Density: 1.019 g/mL at 25 °C(lit.)
• Vapor Pressure: 0.131mmHg at 25°C
• Refractive Index: n20/D 1.523(lit.)
• Storage Temp.: 2-8°C
• Solubility: 0.74mg/l
• Water Solubility: Miscible with chloroform, dichloromethane, ethyl acetate, alcohol and ether. Immiscible with water.
• Sensitive: Air Sensitive
• BRN: 1071910
• CAS DataBase Reference: Phenylpropyl aldehyde(CAS DataBase Reference)
• NIST Chemistry Reference: Phenylpropyl aldehyde(104-53-0)
• EPA Substance Registry System: Phenylpropyl aldehyde(104-53-0)

Safety Data

• Hazard Codes: Xi
• Statements: 36/38-36/37/38
• Safety Statements: 26-36-37/39
• WGK Germany: 2
• RTECS: MW4890000
• F: 10-23
• TSCA: Yes
• Hazardous Substances Data: 104-53-0(Hazardous Substances Data)

Usage

Chemical Properties

Different sources of media describe the Chemical Properties of 104-53-0 differently. You can refer to the following data:
1. Pale Yellow Oil
2. Phenylpropyl aldehyde occurs in Sri Lanka cinnamon bark oil, among others. The aldehyde is a colorless liquid with a strong, floral, slightly balsamic, heavy hyacinth-like odor. It tends to undergo self-condensation. Dihydrocinnamaldehyde can be obtained with scarcely any byproducts by selective hydrogenation of cinnamaldehyde. It is used in perfumery for hyacinth and lilac compositions.
3. 3-Phenylpropionaldehyde has a strong, pungent, floral odor reminiscent of hyacinth with a balsamic, green, warm (almost burning) flavor.

Occurrence

Reported found in the essential oil of Ceylon cinnamon and in strawberry. Also reported found in tomato, cinnamon, cassia leaf, Gruyere de Comte cheese, beer, cooked trassi, origanum (Spanish) and strawberry.

Uses

3-Phenylpropanal (cas# 104-53-0) is a compound useful in organic synthesis.

Preparation

From phenyl propionitrile; also from cinnamic aldehyde diethylacetal.

Taste threshold values

Taste characteristics at 20 ppm: green, melon, fruity and citrus.

Synthesis Reference(s)

Chemical and Pharmaceutical Bulletin, 42, p. 1041, 1994 DOI: 10.1248/cpb.42.1041Tetrahedron Letters, 35, p. 1275, 1994 DOI: 10.1016/0040-4039(94)88042-5

General Description

Hydrocinnamaldehyde is C=C double bond hydrogenated cinnamaldehyde. It has been synthesized by the selective hydrogenation of C=C double bond of cinnamaldehyde by various methods. Hydrocinnamaldehyde and nitromethane undergoes Henry reaction to form nitroaldols. The C1 and C3 position labelled with 13C of hydrocinnamaldehyde was subjected to mass spectrometry and the fragmentation pattern was elucidated.

InChI:InChI=1/C9H10O/c10-8-4-7-9-5-2-1-3-6-9/h1-3,5-6,8H,4,7H2

Upstream product

• 14371-10-9 (E)-3-phenylpropenal 
• 122-97-4 3-Phenyl-1-propanol 
• 63888-20-0 3-phenyl-1-propen-1-yl acetate 
• 95430-20-9 2-phenethyl-1,3-diphenyl-imidazolidine 
• 100-42-5 styrene 
• 201230-82-2 carbon monoxide 
• 5830-31-9 N,N-dimethyl-3-phenylpropanamide 
• 2046-33-5 3-methoxypropylbenzene 
• 51075-28-6 2-bromo-3-phenylpropanal 
• 2430-16-2 6-phenyl-1-hexanol 
• 30076-98-3 (3,3-dimethoxypropyl)benzene 
• 17376-04-4 2-phenethyl iodide 
• 19261-37-1 2-chloro-3-phenyl-propionaldehyde 
• 102-92-1 cinnamoyl chloride 

Downstream Products

• 64299-64-5 2-benzyl-5-phenyl-penta-2,4-dienal 
• 14152-90-0 isonicotinic acid-(3-phenyl-propylidenehydrazide) 
• 102241-44-1 2-(3-phenyl-propylidenamino)-benz[de]isoquinoline-1,3-dione 
• 363138-51-6 ethyl 6-methyl-2-oxo-4-(1-phenylethyl)-1,2,3,4-tetrahydropyrimidine-5-carboxylate 
• 54313-73-4 3-phenyl-1-(pyridin-2-yl) propan-1-ol 
• 4360-60-5 2-phenethyl-[1,3]dioxolane 
• 53376-62-8 ethyl 3-hydroxy-5-phenylpentanoate 
• 60340-28-5 1-phenylhex-5-en-3-ol 
• 64116-27-4 1-anilino-3-phenyl-propane-1-sulfonic acid ; sodium-salt 
• 107456-11-1 2-cyano-5-phenyl-pent-2-enoic acid ethyl ester 
• 175403-27-7 N,N'-(3-phenyl-propylidene)-bis-carbamic acid diethyl ester 
• 32861-51-1 benzyl-(3-phenyl-propyl)-amine 
• 21991-31-1 2-benzyl-3-phenylpropan-1-ol 
• 99902-35-9 5-phenylpent-1-yn-3-ol 

Relevant articles and documents

Cluster Catalysed Selective Transfer Hydrogenation of α,β-Unsaturated Aldehydes

H4Ru4(CO)8L4 (L=PBun3) catalyses selective transfer hydrogenation of α,β-unsaturated aldehydes to α,β-unsaturated alcohols; kinetic and deuterium labelling studies indicate involvement of cluster intermediates and no participation by the cluster hydrides.

Oxidative deprotection of tetrahydropyranyl and trimethylsilyl ethers in water using 1,4-dichloro-1,4-diazoniabicyclo[2,2,2]octane bis-chloride under neutral conditions

The oxidative deprotection of trimethylsilyl and tetrahydropyranyl ethers in water using 1,4-dichloro-1,4-diazonia-bicyclo[2,2,2]octane bis-chloride as a new efficient reagent under neutral conditions is described. The DABCO was regenerated, rechlorinated and reused several times.

Synthesis and fungicidal activity study of novel daphneolone analogs with 2,6-dimethylmorpholine

A series of novel daphneolone analogs was designed and synthesized on the basis of natural product 1,5-diphenyl-2-penten-1-one (I) from Stellera chamaejasme L. as lead compound, whereby 2,6-dimethylmorpholine moiety was introduced to replace 1-phenyl group. Their structures were confirmed by IR, 1H NMR, and HRMS (ESI) or elemental analysis, 13C NMR for some representative compounds. The two isomers of target compounds were separated and identified by NOESY technique and chemical method. All of the synthesized compounds have been evaluated for anti-plant pathogenic fungi activities. The results showed that some compounds exhibited moderate to good antifungal activities against tested fungi at the concentration of 50 mg/L. Among them, compound 7d, with a 4-bromine-substituted phenyl group and cis-2,6-dimethylmorpholine moiety, displayed best activity with an EC50 of 23.87 μmol/L against Valsa Mali, superior to lead compound I. In addition, preliminary structure-activity relationship analysis indicated that, between two isomers of target compounds, the antifungal activities of the isomer with cis-2,6-dimethylmorpholine were better than the trans-isomer.

Simple and efficient water soluble thioligands for rhodium and iridium catalyzed biphasic hydrogenation

The activity of catalytic systems derived from the interaction between Rh(CO)2acac and [Ir(COD)Cl]2, respectively, with the water soluble thioligands (L)-Cysteine (1) and (S)-Captopril (2), was tested in the aqueous biphasic hydrogenation of some representative α,β-unsaturated compounds as 2-cyclohexen-1-one (I), trans-cinnamaldehyde (V) and [3-(1,3-benzodioxol-5-yl)-2-methylpropenal] (X), precursor of the fragrance Helional (XI). The precatalyst Rh/Cap was able to hydrogenate cyclohexenone even at low pressure at 60 °C in a neutral medium while Rh/Cy required either higher pressure and temperature or an alkaline medium. The iridium based catalysts, Ir/Cy and Ir/Cap, showed an analogous trend though their activities were lower than those of the related rhodium catalysts. All the catalysts were easily recycled without significant loss of activity. The rhodium catalysts were also used in the hydrogenation of the above aldehydes V and X and their activity was strongly enhanced when ethylene glycol was used as organic solvent or co-solvent.

Nanosized transition metals in controlled environments of phyllosilicate-mesoporous silica composites as highly thermostable and active catalysts

Stabilization of transition metals in nano-phyllosilicate phases generated by digestion of mesoporous silica is reported as an efficient route for the formation of highly dispersed metallic nanoparticles with outstanding catalytic activity. The Royal Society of Chemistry.

Dendritic nanoreactor encapsulating Rh complex catalyst for hydroformylation

A Rh phosphine complex was encapsulated within the surface alkylated poly(propylene imine) dendrimers through ionic interactions. The resulting dendrimer complexes functioned as nanoreactors for hydroformylation of olefins. The congested surface of dendrimers with long alkyl chains favored hydroformylation of higher olefins. One-pot three reactions composed of hydroformylation, the Knoevenagel reaction, and hydrogenation proceeded within the dendritic nanoreactor. Copyright

Perchloric acid adsorbed on silica gel (HClO4-SiO2) as an inexpensive, extremely efficient, and reusable dual catalyst system for acetal/ketal formation and their deprotection to aldehydes/ketones

Perchloric acid adsorbed on silica gel (HClO4-SiO2) is reported as extremely efficient, inexpensive, and reusable catalyst for dual role for protection of aldehydes/ketones (with trialkyl orthoformates) as acetals/ketals and deprotection (with water-alcohol) to regenerate the carbonyl compounds in high yields at room temperature and in short times. Acetalization/ketalization of electrophilic aldehydes/ketones was carried out under solvent-free conditions. Weakly electrophilic aldehydes/ketones and aldehydes having a substituent that can coordinate with the catalyst, required the corresponding alcohol as solvent. Georg Thieme Verlag Stuttgart.

DABCO-bromine complex: A novel oxidizing agent for oxidative deprotection of THP and silyl ethers and semicarbazones to corresponding carbonyl compounds

A tetrameric DABCO-bromine complex was synthesized, characterized, and utilized as a novel active bromine complex for the oxidative deprotection of THP and silyl ethers and semicarbazones to carbonyl compounds. Copyright Taylor & Francis Group, LLC.

SYNTHESIS AND PHOTOCHEMISTRY OF 2,3,8,9-TETRAHYDROINDENONE-1

The novel β,γ,δ,ε-unsaturated ketone (2) was prepared and all its photoproducts were identified, following wavelength dependent, irradiation-induced transformations.

Selective hydrogenations on heterogenized ruthenium complexes

The heterogenized versions of [RuCl2(PPh3) 3] and [{RuCl2(TPPMS)2}2] were prepared and applied in the selective hydrogenation of α, β-unsaturated aldehydes. Depending on the conditions the above heterogenized catalysts could hydrogenate selectively either the C=O or the C=C bonds, similar to the results obtained in aqueous biphasic systems. Meanwhile the heterogenized catalysts show all the advantages that we can expect from a heterogeneous catalyst: good performance, easy separation, and the possibility of recycling. The effect of H2 pressure on the selectivity was also studied.

A Low Rhodium Content Smart Catalyst for Hydrogenation and Hydroformylation Reactions

Abstract: This paper describes the preparation, broad characterization and study of activity in hydrogenation and hydroformylation reactions of an easily produced 0.18% Rh/Al2O3. Analytical studies on fresh and recycled samples shed light on the smart properties of such catalyst. Results showed high activity as well as fine/excellent chemoselectivity or regioselectivity, characteristics that may suggest a wide range of applicability. Graphic Abstract: The low metal content catalyst 0.18% Rh/Al2O3 was very active in both hydrogenation and hydroformylation reactions so providing intermediates for valuable APIs, as Nabumetone and Eletriptan, and a fragrance with a fresh, green-floral smell, that recalls scent of lily of the valley.[Figure not available: see fulltext.]

Platinum nanocrystals supported on CoAl mixed metal oxide nanosheets derived from layered double hydroxides as catalysts for selective hydrogenation of cinnamaldehyde

Pt nanoparticles supported on sheetlike mixed metal oxides (MMO) derived from layered double hydroxides are found to be highly efficient catalysts for the selective hydrogenation of cinnamaldehyde. A series of characterizations are employed to investigate the structure and composition of the support and catalyst. Divalent species have a significant influence on the activity and selectivity. CoAl MMO-supported catalysts achieve an increase in both conversion and selectivity to cinnamyl alcohol through the formation of PtCo alloy on the surfaces of catalysts during preparation. A possible reaction path is proposed. The effects of Co/Al ratio and calcination temperature on catalytic performance are researched in this work.

Chemoselective flow hydrogenation of Α,Β – Unsaturated aldehyde with nano-nickel

Herein, it is presented a novel catalytic system for the continuous-flow chemoselective hydrogenation of α,β – unsaturated aldehydes used in the production of high-value cosmetics and pharmaceuticals precursors. The reaction was catalyzed by nano-nickel particles grafted on polymeric support, synthesized via a simple, adaptable and green methodology. The system was highly active and very selective to C[dbnd]C bond saturation.

Heavy-Metal-Free Fischer-Tropsch Type Reaction: Sequential Homologation of Alkylborane Using a Combination of CO and Hydrides as Methylene Source

Carbon homologation reactions occur within the well-known Fischer-Tropsch process, usually mediated by transition metal catalysts at high temperature. Here we report the low-temperature, heavy-metal-free homologation of a carbon chain using CO as a C1-source showing for the first time that transition-metal catalysts are not required for Fischer-Tropsch-type reactivity. Reaction of an alkylborane in the presence of either LiHBEt3 or LiAlH4 resulted in multiple CO insertion/reduction events to afford elongated chains by more than two methylene (-CH2-) units, affording aldehyde products upon oxidative aqueous workup. Theoretical and experimental mechanistic studies indicate that the boron terminus is responsible for CO incorporation as well as sequential hydride delivery leading to reduction of acylborane intermediates to alkylboranes.

Cofactor-Free, Direct Photoactivation of Enoate Reductases for the Asymmetric Reduction of C=C Bonds

Enoate reductases from the family of old yellow enzymes (OYEs) can catalyze stereoselective trans-hydrogenation of activated C=C bonds. Their application is limited by the necessity for a continuous supply of redox equivalents such as nicotinamide cofactors [NAD(P)H]. Visible light-driven activation of OYEs through NAD(P)H-free, direct transfer of photoexcited electrons from xanthene dyes to the prosthetic flavin moiety is reported. Spectroscopic and electrochemical analyses verified spontaneous association of rose bengal and its derivatives with OYEs. Illumination of a white light-emitting-diode triggered photoreduction of OYEs by xanthene dyes, which facilitated the enantioselective reduction of C=C bonds in the absence of NADH. The photoenzymatic conversion of 2-methylcyclohexenone resulted in enantiopure (ee>99 %) (R)-2-methylcyclohexanone with conversion yields as high as 80–90 %. The turnover frequency was significantly affected by the substitution of halogen atoms in xanthene dyes.

Efficient preparation and application of monodisperse palladium loaded graphene oxide as a reusable and effective heterogeneous catalyst for suzuki cross-coupling reaction

A homogeneously dispersed graphene oxide supported palladium nanomaterial (Pd?GO) has been successfully synthesized and used as a catalyst in cross-coupling reactions at room temperature. Various analytical techniques such as X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) were used to characterize the monodisperse Pd?GO. Monodisperse Pd?GO nanomaterials were used for the cross-coupling reactions which brought together organic molecules with functional significance. This catalyst showed superior catalytic activity and stability for these coupling reactions. High product yields, short reaction times and mild reaction conditions, obtained by the using of developed catalysts. Importantly, the catalyst can be used at least five experiments successfully without losing its efficiency.

Pd cluster nanowires as highly efficient catalysts for selective hydrogenation reactions

Palladium is a key catalyst invaluable to many industrial processes and fine-chemical synthesis. Although recent progress has allowed the synthesis of Pd nanoparticles with various shapes by using different techniques, the facile synthesis of Pd nanocrystals and turning them into a highly active, selective, and stable catalyst systems still remain challenging. Herein, we report the highly selective one-pot synthesis of monodisperse Pd cluster nanowires in aqueous solution; these consist of interconnected nanoparticles and may serve as highly active catalysts because of the enrichment of high index facets on the surface, including {443}, {331}, and {221} steps. For the first time, carbon nanotube and I3-Al2O3 immobilized Pd cluster nanowires showed highly enhanced catalytic performance in the liquid-phase selective hydrogenation of cinnamaldehyde and gas-phase hydrogenation of 1,3butadiene relative to immobilized Pd icosahedra and nanocubes, as well as commercial Pd catalysts. Power in the cluster: Monodisperse Pd cluster nanowires, which consist of interconnected nanoparticles (see figure), have been synthesized in aqueous solution and may serve as highly active catalysts due to the enrichment of high index facets on the surface. Carbon nanotube and I3-Al2O3 immobilized Pd cluster nanowires showed enhanced catalytic performance in hydrogenations reactions. Copyright

Facile synthesis of highly stable heterogeneous catalysts by entrapping metal nanoparticles within mesoporous carbon

Cycling instability is a persisting problem in heterogeneous catalysis. Here we report an efficient strategy to enhance the recyclability of the heterogeneous catalysts by in situ entrapment of active nanoparticles in mesoporous carbon. A hard template method was used to fabricate the desired catalyst, where Al2O3 was employed as the template and polyphenols were used as carbon source as well as the stabilizing agent. Based on N2 adsorption/desorption analysis, the catalysts adopt the high surface area of the Al2O3 template and feature mesoporous pores. Additionally, the noble metal nanoparticles (Pd) were found to be well entrapped inside the carbon matrix with good dispersion. The as-prepared catalysts were highly active in various heterogeneous hydrogenations of C=C containing substrates (quinoline, cinnamaldehyde, etc.) and exhibited excellent cycling stability without any significant loss of activity for 10 recycles, which is superior to that of the commercial Pd/C catalyst. the Partner Organisations 2014.

A metal-free transfer hydrogenation: Organocatalytic conjugate reduction of α,β-unsaturated aldehydes

Impressive tolerance is displayed in the efficient and chemoselective organocatalytic transfer hydrogenation of α,β-unsaturated aldehydes in the presence of a Hantzsch dihydropyridine and a catalytic amount of dibenzylammonium trifluoroacetate (see scheme). Various sensitive functional groups such as the nitro, cyano, alkenyl, and benzyloxy groups survive these reaction conditions.

Anaerobic nitroxide-catalyzed oxidation of alcohols using the NO +/NO· redox pair

A new method for alcohol oxidation using TEMPO or AZADO in conjunction with BF3·OEt2 or LiBF4 as precatalysts and tert-butyl nitrite as a stoichiometric oxidant has been developed. The system is based on a NO+/NO· pair for nitroxide reoxidation under anaerobic conditions. This allows the simple, high-yielding conversion of various achiral and chiral alcohols to carbonyl compounds without epimerization and no formation of nonvolatile byproducts.

THE DIMESITYLBORON GROUP IN ORGANIC SYNTHESIS. 3. REACTIONS OF ALLYLDIMESITYLBORANE

Allyldimesitylborane readily yields an anion that is attacked by electrophiles in a regio- and stereospecific fashion.Alkylation is at the γ-position to give trans-vinylboranes that can be oxidised to aldehydes.Reaction with trimethylsilyl chloride gives the new, highly differentiated three carbon synthon, Mes2BCHt:CHCH2SiMe3 also by γ-attack and reaction with benzaldehyde proceeds similarly to give rise to a novel γ-lactol synthesis.

Mild and Selective Catalytic Hydrogenation of the C=C Bond in α,β-Unsaturated Carbonyl Compounds Using Supported Palladium Nanoparticles

Chemoselective reduction of the C=C bond in a variety of α,β-unsaturated carbonyl compounds using supported palladium nanoparticles is reported. Three different heterogeneous catalysts were compared using 1 atm of H2: 1) nano-Pd on a metal-organic framework (MOF: Pd0-MIL-101-NH2(Cr)), 2) nano-Pd on a siliceous mesocellular foam (MCF: Pd0-AmP-MCF), and 3) commercially available palladium on carbon (Pd/C). Initial studies showed that the Pd@MOF and Pd@MCF nanocatalysts were superior in activity and selectivity compared to commercial Pd/C. Both Pd0-MIL-101-NH2(Cr) and Pd0-AmP-MCF were capable of delivering the desired products in very short reaction times (10-90 min) with low loadings of Pd (0.5-1 mol %). Additionally, the two catalytic systems exhibited high recyclability and very low levels of metal leaching.

Enhancing the catalytic performance of Pt/ZnO in the selective hydrogenation of cinnamaldehyde by Cr addition to the support

An enhancement of the catalytic performance of platinum in the liquid phase hydrogenation of cinnamaldehyde has been achieved by modifying a ZnO support by addition of Cr(III) cations. The addition of chromium improves the structural properties of the support (larger surface area) and increases its reducibility, and resulted in a better Pt dispersion. The presence of chromium in the support enhanced the overall catalytic activity, and improved the high selectivity towards the unsaturated alcohol. The increase of the reduction temperature from 473 K to 623 K produces an impressive decrease in the turnover frequency for Pt/ZnO, whereas this value remains practically unmodified for Pt/Cr-Zn. The higher reduction temperature reduces the overall activity in both catalysts, but improves selectivity towards the unsaturated alcohol. The present 5 wt% Pt/Cr-ZnO catalyst showed the best results (in terms of selectivity) published until now without use of reaction promoters. The improved performance of this catalyst is ascribed to an adequate metal-support interaction and to the higher reducibility of the support that opens the possibility of alloy formation.

Aqueous biphasic hydrogenations catalyzed by rhodium and iridium complexes modified with human serum albumin

Water soluble complexes derived from the interaction between Rh(CO)2(acac) and [Ir(COD)Cl]2, respectively, with human serum albumin (HSA), were employed in the aqueous biphasic hydrogenation of α,β-unsaturated compounds as 2-cyclohexen-1-one (I), 2-butenal (V), 3-phenyl-2-propenal (IX) and 3-aryl-2-methyl-2-propenals (XIII and XVII). Both catalytic systems Rh/HSA and Ir/HSA showed to be very active in the hydrogenation of ketone I even at low temperature and hydrogen pressure; in particular, the rhodium based catalyst showed to be very selective affording exclusively cyclohexanone (II). The α,β-unsaturated aldehydes investigated required higher temperature (up to 60 °C) and pressure (5 MPa) to obtain good conversions. In this case Rh/HSA resulted to be more active than Ir based catalyst. In all cases both Rh/HSA and Ir/HSA were easily recycled without significant loss of activity.

An insight into the Meerwein-Ponndorf-Verley reduction of α,β-unsaturated carbonyl compounds: Tuning the acid-base properties of modified zirconia catalysts

A series of catalysts consisting of ZrO2 in pure form or modified by doping with boron or an alkaline-earth metal to enhance their acid and basic properties, respectively, were prepared and used in the Meerwein-Ponndorf-Verley reduction of cinnamaldehyde with 2-propanol, where they exhibited moderate activity and a high selectivity (up to 98%) towards cinnamyl alcohol. The catalyst preparation procedure and its modification (viz. doping with boron or an alkaline-earth metal) were found to delay crystallization and increase the number of hydroxyl groups present on the catalyst surface, and hence its catalytic activity. The surface acid and basic properties of the catalysts were determined by pyridine and carbon dioxide chemisorption, respectively. The most active sites in the studied reaction are seemingly proton (Bronsted) acid sites of medium-high strength formed by modification of the ZrO2 with boron; however, the increased activity thus obtained is accompanied by a loss of selectivity towards cinnamyl alcohol. Modifying ZrO2 with an alkaline-earth metal enhances its basicity, thereby reducing its catalytic activity and increasing its selectivity for the unsaturated alcohol.

Functionalized-1,3,4-oxadiazole ligands for the ruthenium-catalyzed Lemieux-Johnson type oxidation of olefins and alkynes in water

Three arene-ruthenium(II) complexes bearing alkyloxy(5-phenyl-1,3,4-oxadiazol-2-ylamino)(4-trifluoromethylphenyl)methyl ligands were quantitatively obtained through the reaction of (E)-1-(4-trifluoromethylphenyl)-N-(5-phenyl-1,3,4-oxadiazol-2-yl)-methanimine with the ruthenium precursor [RuCl2(η6-p-cymene)]2 in a mixture of the corresponding alcohol and CH2Cl2 at 50 °C. The obtained complexes were fully characterized by elemental analysis, infrared, NMR and mass spectrometry. Solid-state structures confirmed the coordination of the 1,3,4-oxadiazole moiety to the ruthenium center via their electronically enriched nitrogen atom at position 3 in the aromatic ring. These complexes were evaluated as precatalysts in the Lemieux-Johnson type oxidative cleavage of olefins and alkynes in water at room temperature with NaIO4 as oxidizing agent. Good to full conversions of olefins into the corresponding aldehydes were measured, but low catalytic activity was observed in the case of alkynes. In order to get more insight into the mechanism, three analogue arene-ruthenium complexes were synthesized and tested in the oxidative cleavage of styrene. The latter tests clearly demonstrated the importance of the hemilabile alkyloxy groups, which may form more stable (N,O)-chelate intermediates and increase the efficiency of the cis-dioxo-ruthenium(VI) catalyst.

Rh-Catalyzed Regio- and Enantioselective Allylic Phosphinylation

Transition-metal-catalyzed branched and enantioselective allylic substitution of monosubstituted precursors with carbon, nitrogen, oxygen, sulfur, and fluoride nucleophiles has been well-established. However, such a selective carbon-phosphorus bond formation has not been realized probably due to the catalyst deactivation by the strong coordinating nature of phosphinylating reagents. Herein, we report a Rh-catalyzed highly regio- and enantioselective synthesis of allylic phosphine oxides in the presence of a chiral bisoxazoline-phosphine ligand. The application of α-hydroxylalkylphosphine oxides to keep the low concentration of the secondary phosphine oxides is essential for the high yields. The addition of diphenyl phosphoric acid was found to not only activate allylic alcohols but also accelerate the carbon-phosphorus bond formation.

Designing of Highly Active and Sustainable Encapsulated Stabilized Palladium Nanoclusters as well as Real Exploitation for Catalytic Hydrogenation in Water

Abstract: Encapsulated nanoclusters based on palladium, 12-tunstophosphoric acid and silica was designed by simple wet impregnation methodology. The catalyst was found to be very efficient towards cyclohexene hydrogenation up to five catalytic runs with substrate/catalyst ratio of 4377/1 at 50?°C as well as for alkene, aldehyde, nitro and halogen compounds. Graphic Abstract: Silica encapsulated Pd nanoclusters stabilized by 12-tungstophosphoric acid is proved to be sustainable and excellent for water mediated hydrogenation reaction with very high catalyst to substrate ratio as well as TON.[Figure not available: see fulltext.]