(a) Which carbocation is more stable: the carbocation formed by protonation of isoprene at carbon-1 or the carbocation formed by protonation of isoprene at carbon-4? Explain.

(b) Predict the products expected from the addition of one equivalent of HBr to isoprene; explain your reasoning.

(c) Predict the products expected from the addition of one equivalent of HBr to trans-1,3,5-hexatriene; explain your reasoning.

(d) In parts (b) and (c), which are likely to be the kinetically controlled products and which are likely to be the thermodynamically controlled ones? Explain.

Transcribed Image Text:

H₂C H₂C C-CH 3 isoprene CH₂ 4