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The syntheses and dehydrochlorinations of a number of bridgehead-substituted 7,8-dichlorodibenzobicyclo-[2.2.2] octadienes are described. The bridgehead substituents (and corresponding substrates) include (CH 2 ) 2 CO 2 H (14b), (CH 2 ) 3 OCH 3 (16), CH 2 OCH 3 (17), (CH 2 ) 3 OH (12), (CH 2 ) 2 OH (20), and CH 2 OH (22). Base-induced dehydrochlorinations of 14b yield predominantly vinyl chloride resulting from base attack on H at C-8 (remote from the carboxylate anion) similar to observations in previous related studies. Dehydrochlorinations of 16 and 17 yielded the isomeric vinyl chlorides with almost complete loss of regioselectivity. Dehydrochlorinations of 12 and 20 (and to a lesser extent with 22) proceeded with high regioselectivity opposite to that observed for 14b. These results suggest the intervention of intramolecular base-induced eliminations from 12 and 20 and to a lesser degree with 22

The kinetics of reversible nucleophilic thiolate ion (RS - with R=n-Bu, HOCH 2 CH 2 , MeO 2 CCH 2 CH 2 and MeO 2 CCH 2 ) addition to Z-substituded β-nitrostyrenes (Z=4-Me 2 N, 4-MeO, 4-MeS, H, 3-Cl, 4-Cl, 3-CN, 4-CN, and 3-NO 2 ), to form ArCH(RS)CH=NO 2 - , have been measured in water at 20 o C. Rate constants in the forward (k 1 ) and reverse direction (k -1 ) and equilibrium constants (K 1 ) correlate reasonably well with Hammet σ-constants for the non-π-donor substituents but show deviations for the π-donors 4-Me 2 N, 4-MeO, and 4-MeS

The kinetics of nucleophilic addition of hydroxide (k 1 OH ) ion and nitromethide (k 1 NM ) ion to phenyl-substituted β-nitrostyrenes (Z=4-Me 2 N, 4-MeO, H, 3-C1, 4-Br, 4-CN, and 4-NO 2 ) have been measured in water, 50% Me 2 SO-50% water, 70% Me 2 SO-30% water (OH - reaction only), and 90% Me 2 SO-10% water

The hydrolysis of Ph(LG)C=CPh(NO 2 ) (4-LG, LG=Cl, I, SEt, OMe) in basic solution yields the anion of 1,2-diphenyl-2-nitroethanone, PhC(=O)C(=NO 2 − )Ph, by the addition-elimination mechanism of nucleophilic vinylic substitution, while the reaction of base with Ph(SCH 2 CH 2 OH)=CPh(NO 2 ) (4-SCH 2 CH 2 OH) leads to a cyclic intermediate by intramolecular nucleophilic attack by the ionized OH group

The syntheses and dehydrochlorinations of a number of bridgehead-substituted 7,8-dichlorodibenzobicyclo-[2.2.2] octadienes are described. The bridgehead substituents (and corresponding substrates) include (CH 2 ) 2 CO 2 H (14b), (CH 2 ) 3 OCH 3 (16), CH 2 OCH 3 (17), (CH 2 ) 3 OH (12), (CH 2 ) 2 OH (20), and CH 2 OH (22). Base-induced dehydrochlorinations of 14b yield predominantly vinyl chloride resulting from base attack on H at C-8 (remote from the carboxylate anion) similar to observations in previous related studies. Dehydrochlorinations of 16 and 17 yielded the isomeric vinyl chlorides with almost complete loss of regioselectivity. Dehydrochlorinations of 12 and 20 (and to a lesser extent with 22) proceeded with high regioselectivity opposite to that observed for 14b. These results suggest the intervention of intramolecular base-induced eliminations from 12 and 20 and to a lesser degree with 22