72256-08-7

Upstream product

• 16433-43-5 4-phenyl-1-pentanoic acid 
• 591-51-5 phenyllithium 
• 1459-00-3 1-bromo-2-phenylpropane 
• 94-02-0 ethyl 3-oxo-3-phenylpropionate 
• 98-83-9 isopropenylbenzene 
• 120312-73-4 1,4-diphenyl-4-penten-1-one 
• 495-71-6 phenacylacetophenone 
• 53910-00-2 1,4-diphenyl-4-penten-1-ol 
• 3360-54-1 3-bromo-2-phenylprop-1-ene 
• 614-27-7 methyl 3-oxo-3-phenylpropionate 
• 20913-05-7 (Benzoylmethylene)triphenylphosphorane 
• 70-11-1 α-bromoacetophenone 
• 936-59-4 3-chloropropiophenone 
• 138624-40-5 diethyl 1,4-dihydro-2,6-dimethyl-4-(1-phenylethyl)-3,5-pyridinedicarboxylate 

Downstream Products

• 75375-33-6 (2,2-)-1,4-diphenyl-1-pentanone 
• 32375-29-4 2,5-diphenyl-1-hexene 
• 7478-61-7 1,4-diphenylbutan-1-one oxime 

Relevant academic research and scientific papers

Ground-State Electron Transfer as an Initiation Mechanism for Biocatalytic C-C Bond Forming Reactions

The development of non-natural reaction mechanisms is an attractive strategy for expanding the synthetic capabilities of substrate promiscuous enzymes. Here, we report an "ene"-reductase catalyzed asymmetric hydroalkylation of olefins using α-bromoketones as radical precursors. Radical initiation occurs via ground-state electron transfer from the flavin cofactor located within the enzyme active site, an underrepresented mechanism in flavin biocatalysis. Four rounds of site saturation mutagenesis were used to access a variant of the "ene"-reductase nicotinamide-dependent cyclohexanone reductase (NCR) from Zymomonas mobiles capable of catalyzing a cyclization to furnish β-chiral cyclopentanones with high levels of enantioselectivity. Additionally, wild-type NCR can catalyze intermolecular couplings with precise stereochemical control over the radical termination step. This report highlights the utility for ground-state electron transfers to enable non-natural biocatalytic C-C bond forming reactions.

Quaternary Charge-Transfer Complex Enables Photoenzymatic Intermolecular Hydroalkylation of Olefins

Intermolecular C-C bond-forming reactions are underdeveloped transformations in the field of biocatalysis. Here we report a photoenzymatic intermolecular hydroalkylation of olefins catalyzed by flavin-dependent 'ene'-reductases. Radical initiation occurs via photoexcitation of a rare high-order enzyme-templated charge-transfer complex that forms between an alkene, α-chloroamide, and flavin hydroquinone. This unique mechanism ensures that radical formation only occurs when both substrates are present within the protein active site. This active site can control the radical terminating hydrogen atom transfer, enabling the synthesis of enantioenriched γ-stereogenic amides. This work highlights the potential for photoenzymatic catalysis to enable new biocatalytic transformations via previously unknown electron transfer mechanisms.

Iron-Catalyzed, Iminyl Radical-Triggered Cascade 1,5-Hydrogen Atom Transfer/(5+2) or (5+1) Annulation: Oxime as a Five-Atom Assembling Unit

By integration of iminyl radical-triggered 1,5-hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro-tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five-atom units, while showcasing broad substrate scope and good functional group compatibility. The annulation products can be easily converted into many valuable compounds. Moreover, DFT calculation studies are performed to provide some insights into the possible reaction mechanisms for the (5+2) and (5+1) annulations.

Mn-Enabled Radical-Based Alkyl-Alkyl Cross-Coupling Reaction from 4-Alkyl-1,4-dihydropyridines

Highly efficient alkylation of β-chloro ketones and their derivatives was achieved by means of domino dehydrochlorination/Mn-enabled radical-based alkyl-alkyl cross-coupling reaction. In situ-generated α,β-unsaturated ketones and their analogues were identified as the reaction intermediates. Known bioactive compounds, such as melperone and azaperone, could be easily prepared from β-chloropropiophenone in two steps.

Iron-Catalysed Remote C(sp3)?H Azidation of O-Acyl Oximes and N-Acyloxy Imidates Enabled by 1,5-Hydrogen Atom Transfer of Iminyl and Imidate Radicals: Synthesis of γ-Azido Ketones and β-Azido Alcohols

In the presence of a catalytic amount of iron(III) acetylacetonate [Fe(acac)3], the reaction of structurally diverse ketoxime esters with trimethylsilyl azide (TMSN3) afforded γ-azido ketones in good to excellent yields. This unprecedented distal γ-C(sp3)?H bond azidation reaction went through a sequence of reductive generation of an iminyl radical, 1,5-hydrogen atom transfer (1,5-HAT) and iron-mediated redox azido transfer to the translocated carbon radical. TMSN3 served not only as a nitrogen source to functionalise the unactivated C(sp3)?H bond, but also as a reductant to generate the catalytically active FeII species in situ. Based on the same principle, a novel β-C(sp3)?H functionalisation of alcohols via N-acyloxy imidates was subsequently realised, leading, after hydrolysis of the resulting ester, to β-azido alcohols, which are important building blocks in organic and medicinal chemistry.

Metal-free visible light photoredox enables generation of carbyne equivalents via phosphonium ylide C-H activation

Carbyne, an interesting synthetic intermediate, has recently been generated from hypervalent iodine precursors via photoredox catalysis. Given the underexplored chemistry of carbyne, due to the paucity of carbyne sources, we are intrigued to discover a new source for this reactive species from classical reagents-phosphonium ylides. Our novel strategy employing phosphonium ylides in an olefin hydrocarbonation reaction features a facile approach for constructing carbon-carbon bonds through metal-free and benign reaction conditions. Moreover, the hydrocarbonation products were delivered in a highly regioselective manner.

Rhodium-Catalyzed Enantioconvergent Isomerization of Homoallylic and Bishomoallylic Secondary Alcohols

We present herein an unprecedented enantioselective isomerization of homoallylic and bishomoallylic secondary alcohols, catalyzed by a commercially available rhodium-complex and a base. This catalytic redox-neutral process provides an effective access to chiral ketones in high efficiency and enantioselectivity, without the use of any stoichiometric reagent or generation of any waste. For the reaction of homoallylic alcohols, this system achieved not only a stereoconvergent access to chiral ketones bearing a β-stereocenter (up to 95%, 86% ee) but also a concomitant oxidative kinetic resolution of the alcohol substrates (S > 20). In the case of bishomoallylic alcohols, an intriguing ligand-induced divergent reactivity was observed. A terminal-to-internal alkene isomerization promoted by Rh/L7 followed by redox isomerization using Rh/BINAP system produced chiral ketones bearing a γ-stereocenter with high yield and enantioselectivity. Mechanistic studies provided strong support for the redox-isomerization pathway with chain walking of the key alkyl-Rh intermediate.

Charge Distribution Between Formally Identical Fragments: The McLafferty Rearrangement

The McLafferty rearrangement for 2,5-diphenyl-1-hexene and its deuterium labelled analogues has been investigated.The α-methylstyrene fragments originating from different parts of the molecular ion retain the charge with equal probability and afford identical metastable spectra.The geometry of the transition state is discussed.

HYDROCARBON ANALOGUES OF THE TYPE II PHOTOELIMINATIONS OF KETONES. PHOTOCHEMISTRY OF 1-SUBSTITUTED 4-PHENYL-4-PENTENES.

Direct irradiation of 1,4-diphenyl-4-penten-1-ol produces mainly 2-methyl-2,5-diphenyltetrahydrofuran, while benzophenone-sensitized photolysis gives alpha -methylstyrene, acetophenone, and 1,4-diphenyl-1-pentanone. The direct irradiation is postulated to proceed via the radical anion of the alkene. A mechanism for the inefficient triplet state reaction ( PHI equals 0. 0005) is proposed which involves initial hydrogen abstraction by the methylene carbon of the excited alkene to give a 1,4 biradical, which then produces the observed products. The mechanism is analogous to the accepted mechanism for the type II photofragmentation of ketone. The mechanism is supported by solvent effects and deuterium-labeling studies. Two related alkenes, 4-phenyl-4-penten-1-ol and 1,4-diphenyl-4-pentene, show similar photochemical behavior, although they react even less efficiently than 1,4-diphenyl-4-penten-1-ol.