Othman, Dina I. A.;Otsuka, Kota;Takahashi, Shuhei;Selim, Khalid B.;El-Sayed, Magda A.;Tantawy, Atif S.;Okauchi, Tatsuo;Kitamura, Mitsuru published 《Total Synthesis of Eleuthoside A; Application of Rh-Catalyzed Intramolecular Cyclization of Diazonaphthoquinone》 in 2018. The article was appeared in 《Synlett》. They have made some progress in their research.Product Details of 39637-74-6 The article mentions the following:
The first total synthesis of (±)-eleutherol and eleuthoside A, the natural cytotoxic substances extracted from medicinal Indonesian plant, is described. First, the synthesis of (±)-eleutherol has been accomplished in nine steps starting from bromo methoxy aldehyde with the aid of diazo-transfer chem. approach. Second, a metal-catalyzed intramol. cyclization reaction of the corresponding diazonaphthoquinone led to the desired eleuotherol, which served as a precursor to eleuthoside A. Then, several glycosidation routes, using different glucosyl donors, were experimented to reach effective O-glycosidation of eleutherol. The only successful strategy involved Koenigs-Knorr glycosylation using peracetyl glycosyl bromide in the presence of Ag2O and quinoline. This strategy furnished our desired acetylated glycoside of β-configuration, regioselectively. Finally, deacetylation and successive separation of diastereomers were conducted to give eleuthoside A. The experimental procedure involved many compounds, such as (1S)-4,7,7-Trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carbonyl chloride(Chunks or pellets) (cas: 39637-74-6) .
(1S)-4,7,7-Trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carbonyl chloride(Chunks or pellets) (cas: 39637-74-6 Product Details of 39637-74-6) is a chiral derivatizing agent. It can be prepared by reacting (-)-(1S,4R)-camphanic acid with thionyl chloride.
Reference:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics