Abstract
Condensation of 4-hydroxy-2-pyridone (4) with citronellal (10) affords o-quinone methide intermediate 11, which reacts further to give inverse electron Diels-Alder adducts 12 (46%) and 16 (25%) and ene adduct 14 (28%). Oxidation of 12 and 14 by Sammes' procedure affords pyridoxatin analogues 13 (54%) and 15 (48%).