Enolization regioselectivity involving stereoisomeric 4a-methyl-5-methoxyperhydrobenzo[7]annulen-2-ones.
Efficient synthetic routes to the four isomers 17b-20b of the title ketone are described. Entry begins from the Wieland-Miescher homologue 3 whose pair of carbonyl groups are amenable to regiochemical manipulation. The compositions of the reaction mixtures generated under kinetic or thermodynamic control were defined by (1)H NMR analysis subsequent to chromatographic purification. The regiochemical trends are correlated with B3LYP/6-31G* calculations, the results of which conform to the preferred introduction of a 1,2- or 2,3-double bond.
Wang
Xiaozhao
X
Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
Butler
Sean C
SC
Gallucci
Judith C
JC
Paquette
Leo A
LA
D001643:Bridged Bicyclo Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods*; D002845:Chromatography / Q000379:methods; D019295:Computational Biology / Q000379:methods; D007536:Isomerism; D007659:Ketones / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics
C545572:4a-methyl-5-methoxyperhydrobenzo(7)annulen-2-one; D001643:Bridged Bicyclo Compounds; D007659:Ketones; D002244:Carbon