180516-43-2Relevant articles and documents
Formation of 2,2-dimethylchroman-4-ones during the photoinduced rearrangement of some aryl 3-methyl-2-butenoate esters. A mechanistic insight
Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
, p. 1903 - 1910 (2016/04/05)
Several aryl 3-methyl-2-butenoate esters upon irradiation lead to the formation of [1,3]-migrated photoproducts, phenol and, surprisingly 2,2-dimethylchroman-4-one derivatives. The starting photochemical reaction takes place from the singlet excited state of the ester and as a total mechanism two consecutive reaction pathways are proposed. The former involves the photo-Fries rearrangement of the esters in all the solvents studied and, depending on the proticity of the solvent, the latter involves an ESIPT process followed by thermal 6π-electrocyclic reaction and/or thermal (intramolecular oxa-Michael addition) cyclization of the ortho regioisomers photoformed. This second pathway is responsible of the formation of the 2,2-dimethylchroman-4-one derivatives.
Chromenes and chromanones. Part IV.1 The Birch reduction of 2,2-dimethyl-4-chromanone and its 7-substituted analogues
Aniol, Miroslaw
, p. 1069 - 1079 (2007/10/03)
2,2-Dimethyl-4-chromanone (1a), 2,2,7-trimethyl-4-chromanone (1b) and 7-methoxy-2,2-dimethyl-4-chromanone (1c) have been reduced by sodium or lithium in liquid ammonia with the presence or without of proton donor. The bicyclic or phenolic products were obtained. Products with reduced benzene ring only were also observed. The possible mechanisms of reductions are considered.
