Electrocyclic reactions. Part IV. Some reactions of 2,4-dibromo-1,5-diphenylpenta-1,4-dien-3-one (αα′-dibromodibenzylideneacetone)

Autor:	Charles W. Shoppee, Burgess J. A. Cooke
Rok vydání:	1973
Předmět:	chemistry.chemical_classification Hydrocarbon Chemistry Reagent Phosphorus Yield (chemistry) chemistry.chemical_element Organic chemistry Conrotatory and disrotatory Medicinal chemistry
Zdroj:	J. Chem. Soc., Perkin Trans. 1. :2197-2202
ISSN:	1364-5463 0300-922X
DOI:	10.1039/p19730002197
Popis:	Treatment of αα′-dibromodibenzylideneacetone (I) with hot hydriodic acid and red phosphorus has been claimed to yield 60% of cis-1,2-diphenylcyclopentane; in fact, the product consists of trans-3,4-diphenylcyclopentanone (24%), which is not reduced by the reagent, 3,4-diphenylcyclopent-2-enone (5%), which is reduced by the reagent to a mixture of cis-1,2-diphenylcyclopentane and a little trans-1,2-diphenylcyclopentane, and a polymeric hydrocarbon of unknown structure (ca. 25%). Treatment of the dibromo-ketone (I) with cold concentrated sulphuric acid furnishes 3-bromo-2-hydroxy-trans-4,5-diphenylcyclopent-2-enone (10%) and trans-2,5-di-bromo-3,4-diphenylcyclopent-2-enone (85%). The primary cyclic products appear to arise by thermal ground state concerted conrotatory [2 + 2] electrocyclic reactions.
Databáze:	OpenAIRE
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