anti-Oligoannelated THF Moieties: Synthesis via Push−Pull-Substituted Cyclopropanes

The first synthesis of anti-fused oligoannelated THF moieties is reported. The key transformation of the synthetic sequence, consisting of cyclopropanation, reduction and oxidation, is the expansion of a push−pull-substituted three-membered ring into a five-membered enol ether system. A repetition of the sequence allows the creation of oligoacetals up to a nonacyclic system.