109248-93-3

Upstream product

• 3375-38-0 1,4-dibenzoylbutane 
• 54120-34-2 trans-1,2-dibenzoylcyclobutane 
• 13735-81-4 1-styrenyloxytrimethylsilane 
• 98-86-2 acetophenone 
• 2270-20-4 5-Phenylpentanoic acid 
• 13633-25-5 1-Bromo-4-phenylbutane 
• 3360-41-6 4-phenyl-butan-1-ol 
• 98-85-1 1-Phenylethanol 
• 14469-83-1 (5-bromopentyl)benzene 
• 100-52-7 benzaldehyde 
• 108-22-5 Isopropenyl acetate 
• 1086221-41-1 1,6-diphenyl-1-hexanol 
• 173409-88-6 (E)-1,6-diphenyl-2-hexen-1-one 
• 16520-62-0 4-Phenyl-1-butyne 

Downstream Products

• 103387-41-3 1,6-diphenyl-hex-1-ene 

Relevant academic research and scientific papers

Palladium-Catalyzed Dual Ligand-Enabled Alkylation of Silyl Enol Ether and Enamide under Irradiation: Scope, Mechanism, and Theoretical Elucidation of Hybrid Alkyl Pd(I)-Radical Species

We report herein that a palladium catalyst in combination with a dual phosphine ligand system catalyzes alkylation of silyl enol ether and enamide with a broad scope of tertiary, secondary, and primary alkyl bromides under mild irradiation conditions by blue light-emitting diodes. The reactions effectively deliver α-alkylated ketones and α-alkylated N-acyl ketimines, and it is difficult to prepare the latter by other methods in a stereoselective manner. The α-alkylated N-acyl ketimine products can be further subjected to chiral phosphoric acid-catalyzed asymmetric reduction with Hantzsch ester to deliver chiral N-acyl-protected α-arylated aliphatic amines in high enantioselectivity up to 99% ee, thus providing a method for facile synthesis of chiral α-arylated aliphatic amines, which are of importance in medicinal chemistry research. The N-acetyl ketimine product also reacted smoothly with various types of Grignard reagents to afford sterically bulky N-acetyl α-tertiary amines in high yields. Theoretical studies in combination with experimental investigation provide understanding of the reaction mechanism with respect to the dual ligand effect and the irradiation effect in the catalytic cycle. The reaction is suggested to proceed via a hybrid alkyl Pd(I)-radical species generated by inner-sphere electron transfer of phosphine-coordinated Pd(0) species with alkyl bromide. This intriguing hybrid alkyl Pd(I)-radical species is elucidated by theoretical calculation to be a triplet species coordinated by three phosphine atoms with a distorted tetrahedral geometry, and spin prohibition rather than metal-to-ligand charge transfer contributes to the kinetic stability of the hybrid alkyl Pd(I)-radical species to impede alkyl recombination to generate Pd(II) alkyl intermediate.

Ruthenium-Catalyzed β-Alkylation of Secondary Alcohols and α-Alkylation of Ketones via Borrowing Hydrogen: Dramatic Influence of the Pendant N-Heterocycle

Three bidentate ruthenium(II) complexes with a pyridonate fragment were prepared and fully characterized. These complexes are structurally similar, but differ in their pendant substituents. Complex 1 contains a phenyl unit, whereas complexes 2 and 3 have uncoordinated thienyl and thiazolyl groups, respectively. These complexes were tested as catalysts for β-alkylation of secondary alcohols with primary alcohols, and 3 shows the highest activity, suggesting the thiazolyl ring participates in the catalytic process. Furthermore, 3 is an excellent catalyst for α-alkylation of ketones with primary alcohols. Various α-alkylated ketones were synthesized in high yields, by using 0.05 mol % 3 and 0.25 equiv of t-BuOK within 30 min.

Photoredox-Catalyzed Decarboxylative Alkylation of Silyl Enol Ethers to Synthesize Functionalized Aryl Alkyl Ketones

Photoredox-catalyzed decarboxylative alkylation of silyl enol ethers has been developed. Diverse functionalized aryl alkyl ketones were afforded in modest to good yields using N-(acyloxy)phthalimide as an easy access alkyl radical source under mild and operationally simple conditions. The excellent performance of drug molecules such as fenbufen and indomethacin and naturally occurring carboxylic acids such as stearic acid and dehydrocholic acid further demonstrated the practicability of the reaction.

Synthesis and catalytic applications of ruthenium(ii)-phosphino-oxime complexes

In this work, the preparation of the first ruthenium complexes containing a phosphino-oxime ligand is presented. Thus, the reaction of cis-[RuCl2(DMSO)4] (3) with 2.4 equivalents of 2-Ph2PC6H4CH=NOH (1) in refluxing THF led to the clean formation of the octahedral ruthenium(ii) derivative cis,cis,trans-[RuCl2{κ2-(P,N)-2-Ph2PC6H4CH=NOH}2] (5), whose structure was unambiguously confirmed by means of a single-crystal X-ray diffraction study. Complex 5 could also be synthesized from the reaction of the dimer [{RuCl(μ-Cl)(η6-p-cymene)}2] (4) with an excess of 1 in refluxing toluene. Treatment of 4 with 2 equivalents of 1, in CH2Cl2 at r.t., allowed also the preparation of the half-sandwich Ru(ii) derivative [RuCl{κ2-(P,N)-2-Ph2PC6H4CH=NOH}(η6-p-cymene)][PF6] (6). In addition, complexes 5 and 6 proved to be active catalysts for the rearrangement of aldoximes to primary amides, as well as for the α-alkylation/reduction of acetophenones with primary alcohols, with the former showing the best performances in both processes.

Oxidation and β-Alkylation of Alcohols Catalysed by Iridium(I) Complexes with Functionalised N-Heterocyclic Carbene Ligands

The borrowing hydrogen methodology allows for the use of alcohols as alkylating agents for C-C bond forming processes offering significant environmental benefits over traditional approaches. Iridium(I)-cyclooctadiene complexes having a NHC ligand with a O- or N-functionalised wingtip efficiently catalysed the oxidation and β-alkylation of secondary alcohols with primary alcohols in the presence of a base. The cationic complex [Ir(NCCH3)(cod)(MeIm(2- methoxybenzyl))][BF4] (cod=1,5-cyclooctadiene, MeIm=1-methylimidazolyl) having a rigid O-functionalised wingtip, shows the best catalyst performance in the dehydrogenation of benzyl alcohol in acetone, with an initial turnover frequency (TOF0) of 1283 h-1, and also in the β-alkylation of 2-propanol with butan-1-ol, which gives a conversion of 94 % in 10 h with a selectivity of 99 % for heptan-2-ol. We have investigated the full reaction mechanism including the dehydrogenation, the cross-aldol condensation and the hydrogenation step by DFT calculations. Interestingly, these studies revealed the participation of the iridium catalyst in the key step leading to the formation of the new C-C bond that involves the reaction of an O-bound enolate generated in the basic medium with the electrophilic aldehyde.

Temporal separation of catalytic activities allows anti-Markovnikov reductive functionalization of terminal alkynes

There is currently great interest in the development of multistep catalytic processes in which one or several catalysts act sequentially to rapidly build complex molecular structures. Many enzymes - often the inspiration for new synthetic transformations - are capable of processing a single substrate through a chain of discrete, mechanistically distinct catalytic steps. Here, we describe an approach to emulate the efficiency of these natural reaction cascades within a synthetic catalyst by the temporal separation of catalytic activities. In this approach, a single catalyst exhibits multiple catalytic activities sequentially, allowing for the efficient processing of a substrate through a cascade pathway. Application of this design strategy has led to the development of a method to effect the anti-Markovnikov (linear-selective) reductive functionalization of terminal alkynes. The strategy of temporal separation may facilitate the development of other efficient synthetic reaction cascades.

Redesign of enzyme for improving catalytic activity and enantioselectivity toward poor substrates: Manipulation of the transition state

Secondary alcohols having bulky substituents on both sides of the hydroxy group are inherently poor substrates for most lipases. In view of this weakness, we redesigned a Burkholderia cepacia lipase to create a variant with improved enzymatic characteristics. The I287F/I290A double mutant showed a high conversion and a high E value (>200) for a poor substrate for which the wild-type enzyme showed a low conversion and a low E value (5). This enhancement of catalytic activity and enantioselectivity of the variant resulted from the cooperative action of two mutations: Phe287 contributed to both enhancement of the (R)-enantiomer reactivity and suppression of the (S)-enantiomer reactivity, while Ala290 created a space to facilitate the acylation of the (R)-enantiomer. The kinetic constants indicated that the mutations effectively altered the transition state. Substrate mapping analysis strongly suggested that the CH/π interaction partly enhanced the (R)-enantiomer reactivity, the estimated energy of the CH/π interaction being -0.4 kcal mol-1. The substrate scope of the I287F/I290A double mutant was broad. This biocatalyst was useful for the dynamic kinetic resolution of a variety of bulky secondary alcohols for which the wild-type enzyme shows little or no activity. The Royal Society of Chemistry 2012.

Base-catalysed ring openings of 1,2-diphenylcycloalkanols having five-, six-, seven- and eight-membered rings

trans-Isomers of 1,2-diphenylcyclopentanol, 5, 1,2-diphenylcyclohexanol, 6, 1,2-diphenylcycloheptanol, 7, and 1,2-diphenylcyclooctanol, 8, have been prepared as have their acyclic analogues, threo- and erythro-3,4-diphenylhexan-3-ol, 9. All structural assignments are confirmed by X-ray crystal structure determinations and experimentally determined structures are compared with the results of empirical force field calculations which also yield strain energies for each of the compounds. With alkali metal dimsyl-dimethyl sulfoxide or 1,3-diaminopropane with its potassium salt as base, the cycloalkanols are isomerised to enolates of corresponding 1,n-diphenylalkan-1-ones, and the acyclic alkanols cleaved to propylbenzene and the enolate of propiophenone. The products are consistent with a polar mechanism involving collapse of alkoxide to expel a benzylic carbanion, followed by one or more proton transfers to yield the observed products. Rates increase in the order, 6 6. Logarithms of relative rates correlate poorly with estimates of strain release in the reactions. Correlations are improved by incorporation of estimates of entropy changes associated with ring opening or cleavage, but remain poor. The fate of isotopic labels in the reactions of 2,n,n-trideuterio-1,2-diphenylcycloalkanols. [2H3]-5, [2H3]-7 and [2H3]-8, shows that protonation of the benzylic carbanion is by solvent DMSO for the cyclooctanol, [2H3]-8, and that competing intramolecular proton transfer occurs in the cycloheptanol, [2H3]-7, and cyclopentanol, [2H3]-5. Kinetic isotope effects associated with the labelling patterns are consistent with a change in rate-limiting step from the initial carbon-carbon bond cleavage in the case of 8, to rate-limiting proton transfer in the case of 5.

Zinc-promoted reactions. 8. The effect of ring strain in the reduction of 1,2-dibenzoylcycloalkanes

Ring cleavage was the main route in the Zn reduction of 1 in neat AcOH, while selective carbonyl reduction predominated in the presence of LiCl. The less strained 2 underwent only carbonyl reduction with Zn/AcOH. The Clemmensen reduction of both 1 and 2 resulted mainly in acyclic products. The unstrained 3 was fairly resistant towards reduction, and did not undergo ring cleavage.