engleski

Chemistry of 1, 3-Dioxepins. II. Dehydrohalogenation of 5, 6-Dihalogen-1, 3-Dioxepanes with Strong Bases

Dehydrohalogenation of 5, 6-dihalogen-1, 3-dioxepanes II with KOH/MeOH or NaOCH3/MeOH under controlled reaction conditions gave mainly 5-halogen-4, 7-dihydro-1, 3-dioxepins III. Further substitution of viniylic-bromine in III with KO-t-Bu/tert-BuOH or KOH/MeOH led to corresponding 5-substituted-4, 7-dihydro-1, 3-dioxepins some of which underwent spontaneous isomerization to 6, 7-dihydro-1, 3-dioxepins. Substitution of viniylic appeared to follow and elimination-addition mechanism with initial formation of an intermediate with a triple bond.

1; 3-Dioxepins; Dehydrohalogenation; 5; 6-Dihalogen-1; 3-dioxepanes

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