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Unformatted text preview: 7 - lO continued (c) trisubstituted - gem-disubstituted 2-methylbut-2-ene i s more stable (d) tetrasubstituted - gem-disubstituted 2,3-di methylbut-2-ene i s more stable 7- 1 1 (a)
= = 2 5 - 20 = 5 kJ/mole (5 .9 - 4.8 = 1 . 1 kcallmole) (b) could not exi st-ring s i ze must be 8 atoms or greater to include trans double bond (c ) Despite the ambiguity of this name, we must assume that the trans refers to t he two methyls since thi s compound can exist, rather than the trans refeni ng to t he alkene, a molecule which could not exist. o(CH3 CH3 2 6 - 20 = 6 kJ/mole ( 6.2 - 4 . 8 = 1 .4 kcallmole) s trained but stable (d) stable-trans i n l O-membered ring (e) unstable at room temperature�annot have trans alkene i n 7-membered ring (possibly i solable a t very l ow temperature-thi s type of experiment i s o ne of the challenges chemi sts attack with gusto) (f) stable-alkene not at bridgehead (g) unstable-violation of B redt's Rule (alkene at bridgehead in 6-membered ring) (h) stable-alkene at bridgehead i n 8-membered ring (i) unstable-violation of B redt's Rule (alkene at bridgehead i n 7-membered ring) 7- 1 2 (a) The di bromo compound should boi l at a higher temperature because of its much l arger molecular weight. (b) The cis should boil at a h i gher temperature than the trans as the trans has a zero dipole moment and therefore no dipole-dipole interactions . (c) 1 ,2-Dichlorocyclohexene should boi l a t a hi gher temperature because o f i ts much l arger molecular weight and larger dipole moment than cyclohexene. 7- 1 3 (a) 0 O�3 N aOH • acetone major E2 m mor E2 1 39 ...
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