11. Radical Reactions

The deuterium kinetic isotope effect for the halogenation of an alkane is defined in the following equation, where X･ = Cl･ or Br･

Predict whether chlorination or bromination would have a greater deuterium kinetic isotope effect.

Predict the product(s) of the following halogenation reactions. Only one equivalent of the halogen is used in each case. If the reaction proceeds selectively, indicate this by only drawing the major product. If the reaction is not selective, draw all possible products.

(b)

Suppose a 2-halobutane was needed for a synthetic sequence. Starting your synthesis with butane, would it be best to put a chlorine or bromine at that position? Explain.

At 600 °C, the ratio of the relative rates of formation of a tertiary, a secondary, and a primary radical by a chlorine radical is 2.6 : 2.1 : 1. Explain the change in the degree of regioselectivity compared to what was found in Problem 44.