Ketones acetylene derivatives

Stabilized lithium acetyhde is not pyrophoric or shock-sensitive as are the transition-metal acetyhdes. Among its uses are ethynylation of halogenated hydrocarbons to give long-chain acetylenes (132) and ethynylation of ketosteroids and other ketones in the pharmaceutical field to yield the respective ethynyl alcohols (133) (see Acetylene-derived chemicals). 

Kotlyarevsky et al. (69TZV927) showed that ketones that are not substituted on the nitrogen of the ring lead to certain complications. Thus, under normal conditions (60CB593), 4-acetyl-3,5-dimethylpyrazole (6) gave a product containing significant quantities of the respective acetylene derivative 11 and an unexpected chloroacetylene 10. 

The above-postulated overall mechanism considers two alternative pathways depending on the nature of the acetylene derivative. Region A outlines a proposal in which the formation of the a-complex intermediate is supported by the fact that the treatment of aliphatic terminal acetylenes with FeCl3 led to 2-chloro-l-alkenes or methyl ketones (Scheme 12). The catalytic cycle outlined in region B invoked the formation of the oxetene. Any attempt to control the final balance of the obtained... 

They noted that in dimethoxyethane or in iso-octane (path a), the major product was dicarbonylcyclopentadienylcobalt (2) which must arise as a result of a retro Diels-Alder reaction of the norbornadiene (which would lead to the formation of acetylene and cyclopentadiene). When the solvent was changed to an aromatic hydrocarbon such as benzene or toluene (path b), the major cobalt-containing product was shown to be a complex derived from Co4(CO)i2, with three CO ligands on an apical cobalt being replaced by a molecule of the aromatic solvent (3). The group noted that they were also obtaining hydrocarbon and ketonic products derived from norbornadiene, acetylene and carbon monoxide .1,2... 

Rupe, H., Glenz, K. Influence of constitution upon the rotatory power of optically active substances. XVI. Acetylene derivatives, ketones and isonitriles. Ann. 1924, 436, 184-204. 

Syntheses and properties of acetylenic derivatives of pyrazoles 02AHC(82)1. Syntheses of 2-pyrazolines by the reactions of a,/ -unsaturated aldehydes, ketones, and esters with diazoalkanes, nitrile imines, and hydrazines 02JHC1. 

Quaternization of quinoxaline is neatly avoided by the synthesis of the azirino[l,2-a]quinoxalines 71 from o-phenylenediamine and the dibromo ketones 70. The azirino compound apparently acts as a 1,3 dipole and undergoes addition with a variety of dipolarophiles to give fused quinox-alines containing a bridgehead nitrogen atom. " Thus the acetylene derivatives 72 give the pyrrolo derivatives 73. The yields are much improved by the use of chloranil in situ to oxidize the presumed dihydro intermediates 74. 

X0 compds., synthesis ketones 31, 888 syntheses with - and acetylene derivs. 31, 644 -, bicyclic... 

Ketones from acetylene derivs. under mild conditions... 

Hydroxymethyl ketones from terminal acetylene derivs. 

The cyclopentadienyl derivatives Cp2TiR have been subject of a long and detailed series of investigations involving synthesis, thermal decomposition pathways, coordination chemistry, and reactivity towards small (organic) substrate molecules (e.g. CO, CO2, CS2, isonitriles, nitriles, ketones, acetylenes). Most of the work has been published and the interested reader is referred to these publications for detailed information [5-11]. 

Additions to 1-acetylene-l-pbosphonium salts Ketones and enamines from acetylene derivatives... 

In 1971 at the University of Strathclyde in Glasgow, Professor Peter Pauson reported on the retro-Diels-Alder reaction of norbomadiene 3 induced by dicobalthexacarbonyl complexes of acetylene or phenylaeetylene 1 to provide dicarbonylcyclopentadienylcobalt complexes 4 in high yield. Almost as an after thought, he mentions In addition to the above products, the reaction of norbomadiene with complexes 1 yields hydrocarbon and ketonic products derived from norbomadiene, acetylene and carbon monoxide. ... 

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