Oxidative spirocyclisation routes towards the sawaranospirolides. Synthesis of ent-sawaranospirolides C and D
作者:Jeremy Robertson、Praful T. Chovatia、Thomas G. Fowler、Jonathan M. Withey、Daniel J. Woollaston
DOI:10.1039/b918091e
日期:——
Two routes are described for the synthesis of the sawaranospirolides, stereoisomeric spirolactone ascorbigenins isolated from Chamaecyparis pisifera. Trapping of the keto enal formed by oxidation of a functionalised 2-(4-hydroxybutyl)furan affords a potential butenolide spiroacetal precursor to sawaranospirolides A and C. Alternatively, epoxidation of protected 3-(dihydropyran-2-yl)-3-arylpropanoic