Copper-Catalyzed Diastereoselective Synthesis of Trifluoromethylated Tetrahydrofurans
The copper-catalyzed intramolecular diastereoselective trifluoromethylcycloetherification of homoallylic alcohols with Togni's reagent as trifluoromethylating reagent was realized under mild conditions. Various trifluoromethylated tetrahydrofurans were synthesized in moderate to good yields. Moreover, a wide range of common functional groups was tolerated.
Wang, Yanan,Jiang, Min,Liu, Jin-Tao
supporting information
p. 1322 - 1327
(2016/04/26)
Catalytic Asymmetric Vinylogous Prins Cyclization: A Highly Diastereo- and Enantioselective Entry to Tetrahydrofurans
We describe the design and development of the first catalytic asymmetric vinylogous Prins cyclization. This reaction constitutes an efficient approach for highly diastereo- and enantioselective synthesis of tetrahydrofurans (THFs) and is catalyzed by a confined chiral imidodiphosphoric acid (IDP). Aromatic and heteroaromatic aldehydes react with various 3,5-dien-1-ols to afford 2,3-disubstituted THFs in excellent selectivity (d.r. > 20:1, e.r. up to 99:1). Aliphatic aldehydes react with similarly excellent results when a highly acidic imidodiphosphorimidate (IDPi) catalyst is used. With a racemic dienyl alcohol, the reaction proceeds via a kinetic resolution. DFT calculations suggest an explanation for unusually high stereoselectivity.
Xie, Youwei,Cheng, Gui-Juan,Lee, Sunggi,Kaib, Philip S.J.,Thiel, Walter,List, Benjamin
supporting information
p. 14538 - 14541
(2016/11/18)
Constituents of holothuroidea, 16. Determination of absolute configuration of the branched methyl group in ante-iso type side chain moiety on long chain base of glucocerebroside from the sea cucumber Holothuria leucospilota
The absolute configuration of the branched methyl group in ante-iso type side chain moiety on the long chain base of glucocerebroside, HLC-2-A, which was isolated from the sea cucumber Holothuria leucospilota was determined. Oxidation of the glucocerebros
Investigation of Aliphatic Dienes by Chemical Ionization with Nitric Oxide
It is shown that the position of the double bond close to the hydrocarbon end of an aliphatic diene functionalized at C(1) can readily be determined by chemical ionization with NO+.Owing to the low abundance of the ions characteristic for the position of the other double bond, its localization may be difficult.Measurement of the chemical ionization (nitric oxide as reagent gas) spectra of the corresponding epoxides or collision activation studies can help.
Budzikiewicz, H.,Blech, St.,Schneider, B.
p. 1057 - 1060
(2007/10/02)
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