Question

1. Rank the following carbocation intermediates in order of incrasing stability and draw important resonance forms when applicable. Classify each as primary, secondary, tertiary, allylic, or benzylic. 2. Rank the following free radical intermediates in order of increasing stability and draw important resonance forms when applicable. Classify each as primary, secondary, tertiary, allylic, or benzylic. CH2 bro ledo IV b III 10 112TV ] 21 3. 2,3-Dimethylbutane reacts with bromine in the presence of light to give a monobrominated product. Predict the structure of the monobrominated product and propose a mechanism for its formation.

Answer 1

(+) Secondary carbocation 'I' 't (+) allylie-Casbocation (+) 'rTr' Primary-carbocation | Телаяу-саяЫocation 'IV Rank of the carbocations in order of Increasing stability 'r , III Primary - сааbоcohoh secondasy- Со я Босоно 1.tv/ Тез кояу с Caa bo co hon "тт? allylie . са Sko cohon

VV becondasy. Allylie Radical more stable Form" Но Benzylic- Radical TIL) Tertiaay. Radical 112' • Primary Radical - 'In Rank of the Radicals in ordea of stability Increasing "IVI Primary Radical 112 TeaHasy- Radical 2 - Allylic Radical Benzylie Radical

(3) Hac - CH – CH – CH3 Bra Hz CH — — CH3 ен, енд К) CH3 CH₃ 2,3-dimethylobutane a-bromo-2, 3-di- methyl- butane 23. dimethylobutane with bromine în Pars of light gives 2-bromo-2,3-dimethyl butane this monoboominated Product sehce

Mechanismo от, му , В. + Вр. of Br H3 C CH - CH₂ не — сH — — ең, ендон, ін, ең, teatasy-Radical of H BY Br. Br H, C— СА — — сну i A3 енен, * Hae CH - CH3 & BP ан, сч, Monor brominated Product