(6S, 7S, 10R)- and (6R, 7S, 10R)-7-isopropyl-10-methyl-4-oxo-1,5-dioxaspiro[5.5]undec-2-enes having an electron-withdrawing substituent at the 2-position: synthesis and use in asymmetric Diels–Alder reactions

Abstract

Chiral spirocyclic dioxinones (S)-(6) and (S)-(7) have been synthesized from (–)-menthone and used in Diels–Alder reactions with cyclopentadiene; remarkable diastereofacial selectivity (isopropyl side) and endo preference observed in these reactions have offered a new methodology for asymmetric Diels–Alder reactions.