51075-29-7

Upstream product

• 34713-70-7 2-Phenylpropanal 
• 121034-40-0 2-Phenyl-2-phenylselanyl-propionaldehyde 
• 121034-41-1 2-(4-Chloro-phenylselanyl)-2-phenyl-propionaldehyde 
• 2085-88-3 2-methyl-2-phenyloxirane 

Downstream Products

• 136705-41-4 (4S,5R)-4-Hydroxy-5-methyl-2-oxy-5-phenyl-4,5-dihydro-isoxazole-3-carboxylic acid ethyl ester 
• 34713-70-7 2-Phenylpropanal 
• 136846-87-2 (RS)-2,5-Dihydro-2,2,5-trimethyl-5-phenyloxazol 

Relevant academic research and scientific papers

Keto-Enol Tautomerization Triggers an Electrophilic Aldehyde Deformylation Reaction by a Nonheme Manganese(III)-Peroxo Complex

Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes, including the biosynthesis of molecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants. In this work, we report a combined spectroscopy, kinetics and computational study on aldehyde deformylation by two side-on manganese(III)-peroxo complexes with bispidine ligands. Both manganese(III)-peroxo complexes are characterized by UV-vis and mass spectrometry techniques, and their reactivity patterns with aldehydes was investigated. We find a novel mechanism for the reaction that is initiated by a hydrogen atom abstraction reaction, which enables a keto-enol tautomerization in the substrate. This is an essential step in the mechanism that makes an electrophilic attack on the olefin bond possible as the attack on the aldehyde carbonyl is too high in energy. Kinetics studies determine a large kinetic isotope effect for the replacement of the transferring hydrogen atom by deuterium, while replacing the transferring hydrogen atom by a methyl group makes the substrate inactive and hence confirm the hypothesized mechanism. Our new mechanism is confirmed with density functional theory modeling on the full mechanism and rationalized through valence bond and thermochemical cycles. Our unprecedented new mechanism may have relevance to biological and biomimetic chemistry processes in general and gives insight into the reactivity patterns of metal-peroxo and metal-hydroperoxo intermediates in general.

Deformylation Reaction by a Nonheme Manganese(III)–Peroxo Complex via Initial Hydrogen-Atom Abstraction

Metal–peroxo intermediates are key species in the catalytic cycles of nonheme metalloenzymes, but their chemical properties and reactivity patterns are still poorly understood. The synthesis and characterization of a manganese(III)–peroxo complex with a pentadentate bispidine ligand system and its reactivity with aldehydes was studied. Manganese(III)–peroxo can react through hydrogen-atom abstraction reactions instead of the commonly proposed nucleophilic addition reaction. Evidence of the mechanism comes from experiments which identify a primary kinetic isotope effect of 5.4 for the deformylation reaction. Computational modeling supports the established mechanism and identifies the origin of the reactivity preference of hydrogen-atom abstraction over nucleophilic addition.

Tunneling Controls the Reaction Pathway in the Deformylation of Aldehydes by a Nonheme Iron(III)-Hydroperoxo Complex: Hydrogen Atom Abstraction versus Nucleophilic Addition

Mononuclear nonheme iron(III)-hydroperoxo intermediates play key roles in biological oxidation reactions. In the present study, we report the highly intriguing reactivity of a nonheme iron(III)-hydroperoxo complex, [(TMC)FeIII(OOH)]2+ (1), in the deformylation of aldehydes, such as 2-phenylpropionaldehyde (2-PPA) and its derivatives; that is, the reaction pathway of the aldehyde deformylation by 1 varies depending on reaction conditions, such as temperature and substrate. At temperature above 248 K, the aldehyde deformylation occurs predominantly via a nucleophilic addition (NA) pathway. However, as the reaction temperature is lowered, the reaction pathway changes to a hydrogen atom transfer (HAT) pathway. Interestingly, the reaction rate becomes independent of temperature below 233 K with a huge kinetic isotope effect (KIE) value of 93 at 203 K, suggesting that the HAT reaction results from tunneling. In contrast, reactions with a deuterated 2-PPA at the α-position and 2-methyl-2-phenylpropionaldehyde proceed exclusively via a NA pathway irrespective of the reaction temperature. We conclude that the bifurcation pathways between NA and HAT result from the tunneling effect in the HAT reaction by 1. To the best of our knowledge, this study reports the first example showing that tunneling plays a significant role in the activation of substrate C-H bonds by a mononuclear nonheme iron(III)-hydroperoxo complex.

Regio-specific ring opening of terpene and aryl-substituted epoxides with Br2/DMS reagent

Tri-substituted terpene and aryl-substituted epoxides react with bromine and dimethyl sulfide to afford α-bromoketones or α-bromoaldehydes as the major products in good yields. The reaction is regio-specific and occurs smoothly in the presence of aromatic

REACTIVITY OF α-ARYLSELENO-ALDEHYDES TOWARDS HALOGENS AND BENZENESELENENYL CHLORIDE

Chlorination of α-seleno-aldehydes bearing an α-hydrogen gives selenium dichlorides which decompose into α-chloro α-seleno-aldehydes and α-chloroenal.Bromination, in all cases, and chlorination for the other α-seleno-aldehydes lead to the α-halogenoaldehydes.