The Cotton Effects of Conjugated Homoannular Dienes. I. The Non-generality of the Rule of Moscowitz

Autor:	J. Lessard, L. Ruest, Ch. R. Engel
Rok vydání:	1972
Předmět:	chemistry.chemical_compound Sodium borohydride Diene chemistry Organic Chemistry Organic chemistry Alcohol General Chemistry Conjugated system Catalysis Cotton effect
Zdroj:	Canadian Journal of Chemistry. 50:1433-1437
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v72-225
Popis:	The non-generality of the diene rule of Moscowitz, relating the helicity of a non-planar conjugated homoannular diene to the sign of its Cotton effect, is discussed. We report the preparation of 3β-bromoacetoxy-16α-ethyl-162-cyano-162,21-cyclo-5α-pregna-17,21-diene, the X-ray crystallographic analysis of which confirms, as reported by Ahmed and Pollard, the stereochemistry which we previously assigned to the parent alcohol and acetate. We also report the synthesis of the methyl ketonic analogues of these dienonitriles and show that their sodium borohydride reduction product still has a Cotton effect in contradiction to the diene rule. The implications of these and other experiments are discussed.
Databáze:	OpenAIRE
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