Synthesis of 7a-aryl-5-<i>t</i>-butyl-3-methyleneoctahydrobenzofuran possessing partial skelotons of some santonin analogue and furanolignans by intramolecular radical cyclisation reaction
octahydrobenzofuran derivatives (1c-6c) possessing the partial skeletons of santonin (7), 11,13-dehydroisohyposantonin (8), dihydrosesamin (9) and lariciresinol (10) have been synthesised by intramolecularradicalcyclisation in good yield via the precursors viz., the trans diaxial bromopropynyl ethers (1b-6b) obtained in highly regio/stereoselective manner.