( f ) The carboxylic acid function plays no part in this reaction; free-radical addition of hydrogen bromide to the carbon – carbon double bond occurs. Recall that hydrogen bromide adds to alkenes in the presence of peroxides with a regioselec-tivity opposite to that of Markovnikov ’ s rule. 19.23 ( a ) The desired product and the starting material have the same carbon skeleton, and so all that is required is a series of functional group transformations. Recall that, as seen in Problem 19.17, a carboxylic acid may be prepared by oxidation of the corresponding primary alcohol. The needed alcohol is available from the appropriate alkene. ( b ) The target molecule contains one more carbon than the starting material, and so a carbon – carbon bond-forming step is indicated. Two approaches are reasonable; one proceeds by way of nitrile formation and hydrolysis, the other by carboxylation of a Grignard reagent. In either case the key intermediate is 1-bromo-2-methylpropane. The desired alkyl bromide may be prepared by free-radical addition of hydrogen bromide to
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This note was uploaded on 09/30/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.