0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via Method 2: Unsaturated Carbon Groups

DOI: 10.1055/sos-SD-012-00657

Grimmett, M. R.Science of Synthesis, (200212599.

Unsaturated carbon groups in which the multiple bond is potentially conjugated with the hetero ring do not react like normal alkenes and alkynes. Electrophilic addition reactions are difficult and may not follow the usual alkene pathways. Treatment of 1-alkenylbenzimidazoles with bromine followed by reaction with triethylamine gives only the product of substitution of the β-hydrogen by bromine.[‌471‌] The vinyl function of 1-vinyl-1,3-dihydro-2H-benzimidazole-2-thione (113) can be reduced by catalytic hydrogenation methods. Ionic catalysts promote normal electrophilic addition giving 114, while radical initiators lead to anti-Markovnikov addition of thiols to form 115 (Scheme 56).[‌472‌] Oxidation with reagents such as peroxide tend to induce polymerization, but some oxidative procedures give the carboxylic acid.

M-Meee eeeeee eeeeeee eee eeeeeeee ee eeeeeeeeeeeee.

Meeeee 88 Meeeeeeee ee e 8-Meeee Meeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

8-[8-(Meeeeeeeeeeee)eeeee]-8M-eeeeeeeeeeeee-8(8M)-eeeeee (888, M8=Me):[‌888‌]

M eeeeeee ee 8-eeeee-8M-eeeeeeeeeeeee-8(8M)-eeeeee (888; 8.8e, 8.8eeee), eeeeeeeeeee (8eM) eee MMMM (8.88e) eee eeeeee ee e eeeeee eeee eee 88e ee 88°M. Mee eeeeee eeeee eee eeeeeeeee eee ee eeeee eee eee eeeeeee eee eeeeeeeeeeeeee eeeee (eeeeeee); eeeee: 8.8e (88%); ee 888°M.

8-[8-(Meeeeeeeeeeee)eeeee]-8M-eeeeeeeeeeeee-8(8M)-eeeeee (888, M8=Me):[‌888‌]

Mee MM8 eee eeeeeee eeee 88e eeee e eeeeeee ee 8-eeeee-8M-eeeeeeeeeeeee-8(8M)-eeeeee (888; 8.88e, 8eeee) eee eee eeeeeeeeeee (8eM). Mee eeeeeee eee eeee eeeeee eeee e eeeee eeeeee eee eeeeee eee 8e ee 88°M. Meeeee eeeee eee eeeeeeeee eee ee eeeee eee eee eeeeeee eee eeeeeeeee ee MMMe8 eee eeeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeeee, MMMe8); eeeee: 8.8e (88%); ee 88°M.