BÀI GIẢNG ORGANIC CHEMISTRY chapter6

ORGANIC CHEMISTRY Dr Nam T S Phan Faculty of Chemical Engineering HCMC University of Technology Office: room 211, B2 Building Phone: 38647256 ext 5681 Email: ptsnam@hcmut.edu.vn Chapter 6: CONJUGATED ALKADIENES A non-polar molecule Reactions of isolated dienes are just like those of alkenes NOMENCLATURE OF ALKADIENES PREPARATION OF 1,3-ALKADIENE Dehydrogenations Eliminations of unsaturated alcohols & alkyl halides ELECTROPHILIC ADDITION REACTIONS Reaction mechanism: 10 11 12 DIELS-ALDER REACTIONS 13 Reactivity of the dienophile is increased if or more electron-withdrawing groups are present Partial positive charge 14 Stereochemistry Racemic mixture 15 In order to participate in a Diels-Alder reaction, the diene must be in an s-cis conformation C1 & C4 are too far apart to react with the dienophile 16 17 Polymerizations 18 ... is increased if or more electron-withdrawing groups are present Partial positive charge 14 Stereochemistry Racemic mixture 15 In order to participate in a Diels-Alder reaction, the diene must be