Sulfones dissolving metal reductions

Benzylic amines are particularly susceptible to hydrogenolysis by catalytic hydrogenation or dissolving metal reduction. " Note that the Wolff-Kishner reduction in 19-61 involved formation of a hydrazone and deprotonation by base led to loss of nitrogen and reduction. Ceric ammonium nitrate in aqueous acetonitrile has also been shown to reductively cleave the V-benzyl group. Primary amines have been reduced to RH with hydroxylamine-O-sulfonic acid and... 

You will appreciate that C02R groups may be removed from these various products by hydrolysis and decarboxylation. The sulfones can be removed by reduction, for example with sodium amalgam in ethanol - this is dissolving metal reduction and works by electron transfer in the style of a Birch reduction. 

The SR substituent can be displaced nucleophilically by amines and hydroxide (867 — 868) and removed reductively by dissolving metals, e.g. from (869) with Zn/H+. Oxidation gives the corresponding sulfoxide and sulfone, in which nucleophilic displacement is easier. Thus, 2- and 4-(phenylsulfonyl)pyrimidines give the corresponding replacement products with various nitrogen and... 

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