75508-81-5

Upstream product

• 2085-31-6 2-diazo-1,3-diphenylpropane-1,3-dione 
• 13665-04-8 2,2-dibromoacetophenone 
• 98-88-4 benzoyl chloride 
• 98-86-2 acetophenone 
• 120-46-7 1,3-diphenylpropanedione 

Downstream Products

• 451-40-1 phenyl benzyl ketone 
• 134-81-6 benzil 

Relevant academic research and scientific papers

Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils

The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.

Spectroscopy and absolute reactivity of ketenes in acetonitrile studied by laser flash photolysis with time-resolved infrared detection

Laser flash photolysis with time-resolved infrared detection of transients (LFP-TRIR) has been used to study the IR spectroscopy and reactivity of a number of substituted ketenes, prepared by the 308-nm photolysis of α-diazocarbonyl precursors in acetonitrile solution at room temperature. The correlation of the experimental ketene asymmetric stretching frequency to the Swain-Lupton field (F) and resonance (R) effect substituent parameters was unsatisfactory, whereas the correlation to the inductive substituent parameter (σ1) of Charton gave excellent results. This suggests that the asymmetric stretching frequency of substituted ketenes depends mainly on the inductive (i.e., field) effect of the substituents. The mechanism and kinetics of the reactions of these ketenes with various amines in acetonitrile were also studied. An intermediate species identified as either zwitterionic ylide or amide enol formed in the nucleophilic addition of the secondary amine to the C(α) of the ketene is observed by TRIR. The decay of this species is assisted by the amine and is concomitant with the formation of an amide, the final product of the reaction. Our kinetic data on ketene amine reactions show a general trend, indicating a much higher reactivity (ca. 3 orders of magnitude difference in the corresponding rate constants) of secondary amines compared with that of tertiary amines. Secondary diethylamine shows reactivity similar to those observed for primary amines, while secondary piperidine seems to be, in general, somewhat more reactive. The observed trend is rationalized in terms of the steric effects exerted by both amine and ketene substituents. Our data on para-substituted phenyl ketenes provide support for the negative charge development on the ketene moiety in the transition state, with electron-withdrawing substituents accelerating and electron-releasing substituents slowing down the addition reaction.

Reaction of lithium alkynolates with acid chlorides: A conventional approach to the preparation of ynol esters

Lithium alkynolates (R-C≡COLi, R = CH3, n-C4H9, t-C4H9, Ph), generated in situ from dibromomethylketones and a strong base, react with electrophiles (diethyl chlorophosphate or benzoyl chloride) with the formation of the corresponding ynol esters.

DURCH STERISCHE EFFEKTE STABILISIERTE β-KETOCARBONSAEUREN

Increasing steric hindrance in β-keto carboxylic acids leads to an increasing kinetic stability towards decarboxylation, till systems are reached wich are completely stable at room temperature.Simultaneously the tautomeric equilibrium is changed in favour of the (Z)-enol, and finally in favour of the (E)-configurated enol.

Cycloadditionen von Phosphacumulenyliden an Acyl- Thioacyl- und Imidoylheterocumulene.

Ketenyliden-triphenylphosphoran 3 reagiert mit dem Acylketen 2 zum Pyronderivat 4.Acyl-, Thioacyl- und Imidoylheterocumulene koennen mit Phosphacumulenyliden 5 2+2-Cycloadditionen zu Vierringsystemen 7 oder 4+2-Cycloadditionen zu Sechsringheterocyclen 8 e