107290-99-3Relevant academic research and scientific papers
SYNTHETIC STUDIES TOWARDS (-)-QUASSIMARIN: AN INTRAMOLECULAR DIELS-ALDER APPROACH TO THE BCE RING SYSTEM
Shishido, Kozo,Takahashi, Kazuyuki,Oshio, Yoshihisa,Fukumoto, Keiichiro,Kametani, Tetsuji,Honda, Toshio
, p. 495 - 508 (2007/10/02)
A novel and a chiral approach to the synthesis of BCE ring system of (-)-quassimarin is described which involves an intramolecular Diels-Alder reaction of the trienic precursor (18) as a key step.The key dihydrofuranone (17) was prepared from L-(+)-diethyl tartrate via 14 step sequence.The quaternary carbon centre in (17) was stereoselectively constructed by magnesium chelation controlled addition of α-lithio-α-methoxyallene to α,β-dialkoxy ketone.Thermolysis of the triene (18) and subsequent hydrolysis provided two tricyclic cycloadducts (19) and (20), both structures were characterized spectroscopically as the corresponding acetates (21) and (22).Particularly, the major adduct (21) was established by the X-ray crystallographic analysis.
