The thermal decomposition reaction of acetone by addition of a small amoumt of carbon disulfide and the order of reaction for thermal decomposition reaction of ketene thus formed have been investigated in detail. Also, the thermal decomposition reaction of acetone was carried out in the current of nitrogen in order to increase the yield of ketene. The result indicated that the rate of formation of ethylene, ethane, as well as ketene was increased than in the case of addition of no nitrogen and this indicated that the decomposition reaction of ketene was effected by the dilution with nitrogen. Further thermodynamical investigations on the thermal decomposition reaction of acetone and ketene have been made and it was confirmed that the thermal decomposition reaction of acetone was the first order reaction and the experimental results can be explained well by supposing the thermal decomposition reaction of ketene is 1.5th order.
Encouraged by the successful synthesis of diazoketone 1, amino diazoketones 3a–3h () were prepared in the same fashion using bromo diazoacetone and alkyl amines. A variety of primary alkyl amines (entry 1–6), as well as a chiral amine (entry 7), and an amino acid-derived amine (entry 8) afforded the corresponding amino diazoketones in good yields.
Synthesis of Ketene by the Pyxolysis of Acetone. IV - JST
To test our hypothesis, we first investigated the synthesis of known diazoketone 1. We found that the desired product could be readily synthesized by aza-Michael addition of benzylamino diazoacetone to ethyl propiolate in ethanol (). Benzylamino diazoacetone (3a) was prepared by the treatment of readily available bromo diazoacetone with an excess of benzylamine.
[2+2] Ketene Cycloaddition - ChemTube3D
Reactions involving ketenes can be categorized into two major types: cycloaddition reactions and nucleophilic additions to ketenes. The so-called Staudinger reaction is a well-known example of a cycloaddition reaction, where a ketene reacts with an imine or a ketone to provide a β-lactam or a β-lactone, respectively. Ketenes can also undergo cycloadditions with alkenes or alkynes to form a C–C bond at the sp center of the ketene.
isolable silyl ketene imines ..
Ketenes, first discovered by Staudinger in 1905, are among the best studied intermediates in organic chemistry. Their versatile reactivity provides access to a number of valuable structural motifs. Ketenes can be readily prepared from several precursors including diazoketones and acid halides, which further underscores their value in synthetic organic chemistry.
Ketene - definition of ketene by The Free Dictionary
Cyclic 6-membered enaminones were synthesized from three components (bromo diazoacetone, primary amine, and alkyne) in high yields via aza-Michael addition, Wolff rearrangement and nucleophilic ketene cyclization.
Ethenone is the formal name for ketene
An efficient synthesis of spiro-fused macrolactams by a multicomponent macrocyclization reaction (MCMR) is reported. The use of highly reactive, transient intermediates in this MCMR permits short reaction times, even at high dilution. The methods employed for this MCMR were first developed as a four-component strategy for the synthesis of β-ketoamide isoxazolines and a new macrocyclization reaction is reported.
This reaction is called as Schmidlin ketene synthesis
AB - Concise syntheses of the DE and GH ring segments of gambierol (1) were achieved by the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate, followed by the hydroboration of the resulting cyclic enol ethers and subsequent lactonization.