Synthesis and conversions of substituted 4,5-dihydro-3H-spiro[benz-2-azepine-3,1′-cyclohexanes]

On oxidizing substituted 1,2,4,5-tetrahydro-3H-spiro[benz-2-azepine-3,1′-cyclohexanes]with potassium permanganate under phase-transfer catalysis conditions the corresponding 4,5-dihydro derivatives are formed in quantitative yield. By the action of allyl- and benzylmagnesium halides 5-methyl-4,5-dihydro-3H-spiro[benz-2-azepine-3,1′-cyclohexane] is converted into 5-methyl-1,2,4,5- tetrahydro-1-allyl(benzyl)-3H-spiro[benz-2-azepine-3,1′-cyclohexane], and by reaction with phenoxyketene and dichlorocarbene into the corresponding 2-oxoazetidino[4,1-a]- and 1,1-dichloroaziridino[3,1-a]benz-2-azepines.