124183-02-4Relevant academic research and scientific papers
Some 6,6-disubstituted 2,4-cyclohexadien-1-ones and the facial selectivity in their Diels-Alder reactions with dimethyl acetylenedicarboxylate
Yates, Peter,Gomes, Anabela,Burnell, Jean D.,Cong, Dong Dao,Sawyer, Jeffery F.
, p. 37 - 47 (2007/10/02)
6,6-Disubstituted 2,4-cyclohexadien-1-ones can be prepared by dibromination-bisdehydrobromination of the corresponding 6,6-disubstituted 2,2-dibromocyclohexanones.Such dienes undergo Diels-Alder reactions with dimethyl acetylenedicarboxylate to give 3,3-disubstituted 5,6-di(methoxycarbonyl)bicycloocta-5,7-dien-2-ones; when the substituents at C-6 in the dienones are different, two diastereomers of the adducts are formed in a ratio dependent on the "facial selectivity" in the Diels-Alder reactions.For the cases where one of the 6-substituents is methyl and the other is methoxycarbonyl, acetoxymethyl, dibromomethyl, or dichloromethyl it has been established via X-ray crystallograpfy and chemical correlation that the endo-3-methyl/exo-3-methyl product ratio is 3.0, 0.9, 8, and 6, respectively.The origin of these differences is discussed briefly and a spectroscopic method for the assignment of structures to the individual diastereomers is proposed.Key words: Diels-Alder reactions, substituted 2,4-cyclohexadien-1-ones, facial selectivity, dimethyl acetylenedicarboxylate.
FUNCTIONALISATION OF UNACTIVATED METHYL GROUPS THROUGH CYCLOPALLADATION REACTIONS
Baldwin, Jack E.,Jones, Richard H.,Najera, Carmen,Yus, Miguel
, p. 699 - 712 (2007/10/02)
The transformation of the organopalladium compound (3) into the corresponding deuteriated, chlorinated, or oxidized derivatives (7), (8), or (9), (11), and (12) respectively, is described.The palladation of compound (9) takes place regioselectively leadin
