Stereodivergent approach to the asymmetric synthesis of bacillariolides: a formal synthesis of ent-bacillariolide II.
[reaction: see text] Asymmetric synthesis of densely functionalized bicyclic frameworks for entry into bacillariolides I/III and ent-bacillariolide II is reported. The key features are ring-closing metathesis of a pair of diastereomerically related dienes obtained through a stereodivergent route from a R-(+)-glyceraldehyde derivative, transformation of a nonstereoselective cyclopentene ester enolate alkylation process to a completely stereoselective one through alkylation of a bulky ester enolate with a bulky electrophile, and a remote silyloxymethyl group directed epoxidation.
Ghosh
Subrata
S
Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India. ocsg@iacs.res.in
Sinha
Saikat
S
Drew
Michael G B
MG
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
D019086:Bridged Bicyclo Compounds, Heterocyclic; D007783:Lactones; C520170:bacillariolide II; C485138:bacillariolide III