LiAlH4, reaction with carbamates

Heating of the benzene solution of 44 and K2CO3 induced the intramolecular Sn2 reaction to afford 6-deoxycodeine 45 in 53% yield (Scheme 10). The major side product in this reaction was, as anticipated, diene 46 (30% yield), which was formed by elimination reaction. It was reported that the solvent effect is significant in the Sn2 reaction when this reaction was carried out in acetonitrile, diene 46 was obtained as the major product. Treatment of 45 with methyl chloroformate provided a methyl carbamate, whose allylic oxidation with Se02 in the presence of f-BuOOH introduced the hydroxy group at C-6 to give 19. PCC oxidation of 19, followed by LiAlH4 reduction, provided racemic codeine. 

Azide 65, an intermediate of the synthesis of lycoposerramine-V, was converted into primary amine by the Staudinger reaction and the resulting amine was directly treated with methyl chloroformate to give methyl carbamate derivative 69 (Scheme 13). Reduction of the carbamate with LiAlH4 gave A-methyl derivative 70 and then the resulting secondary amine was acylated with chloroacetylchloride... 

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