191165-24-9Relevant academic research and scientific papers
An efficient activation of the hydroxyl function by (diethylamino)sulfur trifluoride (DAST): preparation of chiral polyoxygenated tetrahydrofurans by stereoselective benzyloxy group participation
Monthiller, Sophie,Heck, Marie-Pierre,Mioskowski, Charles,Lafargue, Pierre,Lellouche, Jean-Paul,Masella, Michel
, p. 145 - 152 (2007/10/03)
Based on an intramolecular benzyloxy or amide group participation, two sets of experimental conditions have been established for the preparation of cis/trans tetrahydrofurans 6 or lactone 8 from sugar-derived open-chain hydroxylated precursors 4.These include: (1) a two-step mesylation-cyclization promoted by LiOH/THF-H2O or NaI/CH3CN at reflux; or (2) a one-step cyclization mediated by (diethylamino)sulfur trifluoride (DAST) at -78 deg C in CH2Cl2.The scope and limitations of these cyclizations are described particularly in relation to a stereoselective synthesis of highly oxygenated chiral tetrahydrofurans.Molecular modeling studies tentatively rationalized our experimental cyclization results affording five-membered versus six-membered heterocycles starting from different precursors. - Keywords: polyoxygenated tetrahydrofuran; (diethylamino)sulfur trifluoride (DAST); benzyl group participation; amide group participation; L-gulonolactone; differentially protected 1,4-diol
