An Efficient Flow-Photochemical Synthesis of 5<i>H</i>-Furanones Leads to an Understanding of Torquoselectivity in Cyclobutenone Rearrangements
作者:David C. Harrowven、Mubina Mohamed、Théo P. Gonçalves、Richard J. Whitby、David Bolien、Helen F. Sneddon
DOI:10.1002/anie.201200281
日期:2012.4.27
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 photochemicalrearrangement is due a dichotomous reactivity of the (E)‐ and