Ketenes

Protocol rules for ketenes

Methylketene is used as surrogate for ketene photolysis. J(2038) is used for the photolysis of ketenes or compounds with a ketene group and additional non-chromophoric substituents. For the photolysis of polyfunctionals with a ketene and further carbonyl groups, where the ketene group is product-determining, J(2038) is used in conjunction with the respective j values from the other carbonyl groups. For the photolysis of all other polyfunctionals with a ketene group, J(8023) is used together with the j values from the other chromophores and photolysis products are determined by one of the other chromophores (see also wiki page for compounds with polyfunctional chromophores).

If several products are possible for internal Criegee intermediates, the protocol tries to simplify the reactions and uses only the product with the double bond towards the side of (in order of preference):

• the longest branch
• the most heavily branched (alkyl substituted) branch
• the most substituted branch

Return to the main page for additional decision trees of further chromophores.