Acetylenic ketones, reaction with secondary

A rather different reaction of acetylenes is the addition of water, usually catalysed by Hg(II), to give ketones. Terminal acetylenes 41 reliably give methyl ketones 44 as the intermediate vinyl cation 42 is secondary. Water adds to the cation 42 to give the enol 43 which equilibrates to the ketone 44 with the loss of Hg(OAc)2. 

This reaction was initially reported by Favorskii in 1905 and subsequently extended by Babayan in 1939. It is a base-promoted or -catalyzed ethynylation of aldehydes and ketones to produce secondary or tertiary acetylenic alcohols or glycols using anhydrous KOH or NaOH. Therefore, it is generally known as the Favorskii-Babayan reaction or Favorskii reaction. Although it has been proposed that this reaction might involve a reaction between acetylene and the adduct from the ketone and KOH or a coupling of potassium acetylide with the carbonyl compounds, the most recent experimental results indicate that potassium hydroxide and acetylene first form a complex, rather than potassium acetylide in liquid ammonia, which then reacts with carbonyl compounds to form the acetylenic alcohols, where ammonia functions as a co-catalyst. The experimental evidence includes... 

Oxammonium salts such as 81 are new and powerful oxidizing agents for the selective oxidation of alcohols to aldehydes or ketones. 28 Such salts can be generated catalytically from small amounts of a nitro-xide in the presence of a secondary oxidation procedure, either chemical or electrochemical,. 29 or with two equivalents of acid and 2 equivalents of a nitroxide. When 81 was mixed with acetylenic alcohol 82 in dichloromethane, aldehyde 83 was isolated in 93% yield. The reaction can be monitored as the initial yellow slurry changes to a white slurry and the presence of unreacted oxidant can be checked with starch. 3l It is not necessary to use anhydrous conditions, and it was discovered that the rate of reaction was enhanced by the presence of silica gel. This reagent is compatible for the mild oxidation of many alcohols, including aliphatic primary and secondary as well as allylic and benzylic alcohols. 

He showed that sodium salts of aliphatic primary and secondary nitrocompounds react with acids to form carbonyl compounds 2R2CHNO2 = 2R2C0+N2O+ H2O. Nef supported the theory of bivalent carbon. In the preparation of the explosive mercuric salt of nitromethane, he found that mercury fulminate is formed and regarded fulminic acid as C N OH, the reaction being Hg(CH2 N0 0)2==Hg(0-N C)2 + 2H20. He prepared the explosive addition compound of fulminic acid and hydrogen chloride, HON CHCl. In researches on acetylene compounds he prepared explosive di-iodoacetylene, IC-CI (he formulated it IgC.-C). He discovered the reaction between sodium acetylene and a ketone, followed by hydrolysis, to form an acetylenic carbinol ... 

A-Alkylation of amides and amines and dehydrative -alkylation of secondary alcohols and a-alkylation of methyl ketones " have been carried out by an activation of alcohols by aerobic oxidation to aldehydes, with copper(II) acetate as the only catalyst. A relay race process rather than the conventional borrowing hydrogen-type mechanisms has been proposed for the aerobic C-alkylation reactions, based on results of mechanistic studies. A Winterfeldt oxidation of substituted 1,2,3,4-tetrahydro-y-carboline derivatives provides a convenient and efiflcient method for the synthesis of the corresponding dihydropyrrolo[3,2-fc]quinolone derivatives in moderate to excellent yields. The generality and substrate scope of this aerobic oxidation have been explored and a possible reaction mechanism has been proposed. Direct oxidative synthesis of amides from acetylenes and secondary amines by using oxygen as an oxidant has been developed in which l,8-diazabicyclo[5.4.0]undec-7-ene was used as the key additive and copper(I) bromide as the catalyst. It has been postulated that initially formed copper(I) acetylide plays an important role in the oxidative process. Furthermore, it has been postulated that an ct-aminovinylcopper(I) complex, the anti-Markovnikov hydroamination product of copper acetylide, is involved in the reported reaction system. Copper(I) bromide... 

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