Benzyloxycarbonyl group, reductive cleavage

The acid-catalyzed cleavage of the tert-butoxycarbonyl group Is the best method to form the parent benzazepinone. Other methods used have been the Pd/C hydrogenolysis of a benzyloxycarbonyl group,and zinc mediated reductive cleavage of trichloroethoxy and trichloro-tert-butoxy carbonyl groups. ... 

Cleavage of p-nitrobenzyl group. Protection of carboxylic acids and amines as the esters and carbamates can take advantage of the selective reduction-induced fragmentation by zinc dust, as C=C bonds, S-N bonds, benzyloxycarbonyl, and diphenylmethyl groups are not affected during the operation. 

Stevens and Watanabe [126] have investigated the use of the allyloxycarbonyl group, which is electronically similar to benzyloxycarbonyl. Like the latter it may be removed by acid hydrolysis or by reduction with sodium in liquid ammonia. Catalytic hydrogenation results in partial cleavage and partial conversion into the n-propyloxycarbonyl group which is not further affected. 

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