Synthesis of the cyclobutanone core of solanoeclepin A via intramolecular allene butenolide photocycloadditionElectronic supplementary information (ESI) available: experimental details. See http://www.rsc.org/suppdata/ob/b3/b311415e/

The compact tricyclic substructure of solanoeclepin A containing the cyclobutanone ring was prepared by using as the key step a highly regioselective intramolecular [2 + 2]-photocycloaddition reaction between one of the [small pi]-bonds of an allene and the CC double bond of a butenolide.