Go with the flow: 4-Hydroxycyclobutenones were efficiently transformed into 5H-furanones using an inexpensive flow-photochemical setup. The results challenge the notion that this and the related thermochemical rearrangement display torquoselectivity in their electrocyclic opening to a vinylketene intermediate. Selectivity in the photochemical rearrangement is due a dichotomous reactivity of the (E)- and (Z)-vinylketene intermediates (see scheme).
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.