Asymmetric Synthesis of the Ring A Substructure of Genkwadane A. Issue 9 (4th July 2018)

• Record Type: Journal Article
• Authors: Feng, Jing; Yin, Hongli; Man, Yi; Fu, Shaomin; Liu, Bo
• Is Part Of: Chinese journal of chemistry. Volume 36:Issue 9(2018)
• Page Start: 831
• Page End: 836
• Publication Date: 2018-07-04
• Subjects: genkwadane A -- daphnane -- Mukaiyama aldol -- sulfoxidation -- Dieckmann‐type condensation; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cjoc.201800199
• Languages: English
• ISSNs: 1001-604X

Abstract

Abstract: A practical approach to the asymmetric synthesis of the ring A substructure of genkwadane A, a daphnane diterpenoid, was developed. This synthesis features the Mukaiyama aldol reaction to introduce the quaternary stereogenic center at C4 and VO(acac)2 ‐catalyzed Jackson‐Ellman‐Bolm sulfoxidation to deliver the corresponding sulfoxide. The Dieckmann‐type condensation was efficiently promoted by KHMDS and the ring A substructure was finally accomplished through Barton iodination condition. Abstract : Asymmetric synthesis of the ring A substructure of genkwadane A has been accomplished in 10 steps from D ‐tartrate derivative. The key steps feature the Mukaiyama aldol reaction to introduce the quaternary chiral center at C4 and VO(acac)2 ‐mediated enantioselective Jackson‐Ellman‐Bolm sulfoxidation to furnish a R ‐configured sulfoxide. The crucial Dieckmann‐type condensation was well applicable to the R ‐configured sulfoxide, which successfully delivered the five‐membered skeleton under the condition of KHMDS. The ring A substructure was finally accomplished through Barton iodination condition.