3,4,5,6-Tetrahydro-2H-3,6-epoxybenzo[g][1,4]oxazocine – A new bridged heterocyclic system

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Salicylic aldehydes readily undergo alkylation with bromoacetaldehyde diethyl acetal, subsequent [3+2]-cycloaddition with nonstabilized azomethine ylide and consequent hydrolysis of the oxazolidine and acetal groups leads to 4-methyl and 4-benzyl-3,4,5,6-tetrahydro-2H-3,6-epoxybenzo[g][1,4]oxazocines in 15–65 % overall yields. N-Unsubstituted oxazocines were prepared by the Henry reaction of the alkylated salicylic aldehydes followed by reduction and hydrolysis in 22–40 % overall yields based on starting salicylic aldehyde.