Ethylene derivatives ketones

In Robinson s now well-known suggestions, regarding the processes by which alkaloids may be produced in plants, two main reactions are used j the aldol condensation and the similar condensation of carbinol-amines, resulting from the combination of an aldehyde or ketone with ammonia or an amine, and containing the group. C(OH). N., with substances in which the group, CH. CO. is present. By these reactions it is possible to form the alkaloid skeleton, and the further necessary changes postulated include oxidations or reductions and elimination of water for the formation of an aromatic nucleus or of an ethylene derivative. 

In Chart 7 we included a short series of benzylidenemalononitriles as well as a-nitrostilbenes.116 Note that the most common functionalities associated with the chemistry of the nucleophilic addition to the C=C bond, namely aldehydes, ketones, esters, anhydrides and nitriles, are EW substituents present in dienophiles and dipolarophiles used in NED DA and 1,3 dipolar cycloadditions, and they are included in Table l.121 In Table 14, we summarize the global properties and local electrophilicity values for the series of benzylidenemalononitriles and a-nitrostilbenes. Both series present ethylene derivatives with large electrophilicity values, to > 2.3 eV, they being classified as strong electrophiles within the theoretical electrophilicity scale.39... 

Hydrogenation of ethylene derivatives s. 3, 610 Selective hydrogenation and reduction Ketones and ethylene sec. alcohols from ethylene ketones s. 4, 67 C C —>- CHCH... 

Reaction of boranes with diazo compounds Synthesis of ketones from ethylene derivatives... 

A soln. of the startg. m. and 4 equivalents ketal heated ca. 8 hrs. at 100° in toluene containing 2,4-dinitrophenol as catalyst, and the intermediate ketone treated at 0° with NaBH4 in methanol > product. Y up to 81% purity 98%. -This olefinic ketal Claisen reaction is useful for preparing trans-disubst as well as trans-trisubst. olefinic bonds. The above producure is the last of a succession of 3 similar steps. F. e. and catalysts s. W. S. Johnson et al., Am. Soc. 92, 4463 (1970) Proc. Natl. Acad. Sci. U.S. 67, 1462, 1465, 1810, 1824 (1970) geospecific synthesis of ethylene derivs., review, s. J. Reucroft and P. G. Sammes, Quart. Rev. 25,135 (1971). 

Sodium dichromate/sulfuric acid-mercuric propionate Ketones from ethylene derivs. 

Methyl ketones from terminal ethylene derivs. 

Trime thy Ich lo rosiIan efzin c Ethylene derivs. from ketones... 

Methyl ketones from terminal ethylene derivs. CH CH2 COCH3... 

Cyclopropyl silyl ketones from electron-deficient ethylene derivs. and a-halogenacylsilanes... 

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