Benzylamines, photolysis

These benzylamines have been used for the protection of adenine and can be cleaved by photolysis at 254 nm. ... 

The generation of ketenes was confirmed, as illustrated in Scheme 29, by trapping experiments with methanol or benzylamine, producing the methyl ester or amide 196. Upon photolysis of precursor 194 (R = Ph R = H), the formation of phenyl ketene, which was monitored by IR spectroscopy, was indicated by the appearance of the C=C=0 band at 2120 cm. The even more efficient generation of ketenes was also achieved by photolysis of the selenium analogues of compounds 194. 

A new synthesis of ( )-crinan (43), a compound possessing the basic ring skeleton of the alkaloid crinine, using a stereoselective photocyclization reaction has been devised.28 The imine (39), readily prepared from 2-allylcyclohexanone and benzylamine, was acetylated with piperonyloyl chloride to give the AT-acylena-mine (40). Photolysis of (40) in methanol solution gave compound (41) (15% yield) whose structure and stereochemistry were established by spectral means and by consideration of the proposed electrocyclic nature of the reaction. 

Amine bases generated by the photolysis of carbamates, O-acyloximes, ammonium salts, formanilides, aminoimides, a-aminoketones, and amidines have been used to catalyze a wide range of different condensation polymerization reac-tions. Scheme 5 shows a mechanism for the photolysis of an O-acyloxime, 8, as a photolatent base to produce benzylamine. 

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