Synthesis of Octahydrobenzo[b]furans Using Tandem Conjugate Addition Reactions Initiated by Oxygen Nucleophile

Abstract

When 1-nitrocyclohexene (1) was treated with methyl 4-hydroxy-2-butynoate (2) in the presence of potassium tert-butoxide in tetrahydrofuran-tert-butanol at 0°C for 10 min, a tandem conjugate addition product, methyl cis-3a-nitrooctahydrobenzo[b]furan-Δ^{3, α}-acetate (3a), was obtained in quantitative yield as a 55 : 45 mixture of the (Z)- and (E)-isomers. The scope and limitations of this reaction were examined. Some transformation reactions of 3a are also described.