Stereoselective total synthesis of trans-2-aryl-6-alkyl tetrahydropyran (THP) natural products (±)-6-epi-goniothalesdiol A (3) and (±)-parvistone E (2) has been achieved from the readily available allylic alcohol (±)-8 in 8 and 9 steps in overall yield of 20.9% and 9.4%, respectively. A direct intramolecular oxidative cycloetherification reaction of (E)-1-aryl-5-hydroxyalkene (±)-7 promoted by 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as an oxidant proceeds via a 6-endo-trig pathway cleanly to construct the rare and challenging trans-2-aryl-6-alkyl-3,4-dihydropyran framework (±)-6 in 70% yield and with good diastereoselectivity (trans/cis = 75:25).
