Electrocyclic reactions. Part III. Some reactions of 2,4-dimethyl-1,5-diphenylpenta-1,4-dien-3-one (αα′-dimethyldibenzylideneacetone)
- 1 January 1973
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- p. 1026-1030
- https://doi.org/10.1039/p19730001026
Abstract
αα′-Dimethyldibenzylideneacetone (I) by treatment with hot hydrochloric acid givestrans-2,5-dimethyl-3,4-diphenylcyclopent-2-enone (Va). With hot hydriodic acid the minor product is the cyclopentenone (Va) and the major product is trans-2,5-dimethyl-trans-3,4-diphenylcyclopentanone (VIa). The cyclopentenone (Va) undergoes only partial reduction with hot hydriodic acid to the cyclopentanone (VIa). The results suggest a conrotatory thermal ground state electrocyclisation of a pentadienyl cation to a cyclopentenyl cation, followed by loss of a proton and ketonisation, or by reduction. The high yields of cyclic products, relative to those observed for trans,trans-dibenzylideneacetone, are notable.Keywords
This publication has 0 references indexed in Scilit: