95257-22-0Relevant articles and documents
Mild C–C Bond Formation via Lewis Acid Catalyzed Oxetane Ring Opening with Soft Carbon Nucleophiles
Huang, Hai,Zhang, Tianyu,Sun, Jianwei
supporting information, p. 2668 - 2673 (2020/12/07)
Mild oxetane opening by soft carbon nucleophiles has been developed for efficient C?C bond formation. In the presence of LiNTf2 or TBSNTf2 as catalyst, silyl ketene acetals were found to be effective nucleophiles to generate a wide range of highly oxygenated molecules, which are key substructure in natural products like polyketides. Furthermore, intramolecular oxetane opening by a styrene-based carbon nucleophile via a Prins-type process was also achieved with Sc(OTf)3 as catalyst, leading to efficient formation of the useful 2,3-dihydrobenzo[b]oxepine skeleton.
Highly Enantioselective, Hydrogen-Bond-Donor Catalyzed Additions to Oxetanes
Strassfeld, Daniel A.,Wickens, Zachary K.,Picazo, Elias,Jacobsen, Eric N.
supporting information, p. 9175 - 9180 (2020/07/13)
A precisely designed chiral squaramide derivative is shown to promote the highly enantioselective addition of trimethylsilyl bromide (TMSBr) to a broad variety of 3-substituted and 3,3-disubstituted oxetanes. The reaction provides direct and general access to synthetically valuable 1,3-bromohydrin building blocks from easily accessed achiral precursors. The products are readily elaborated both by nucleophilic substitution and through transition-metal-catalyzed cross-coupling reactions. The enantioselective catalytic oxetane ring opening was employed as part of a three-step, gram-scale synthesis of pretomanid, a recently approved medication for the treatment of multidrug-resistant tuberculosis. Heavy-atom kinetic isotope effect (KIE) studies are consistent with enantiodetermining delivery of bromide from the H-bond-donor (HBD) catalyst to the activated oxetane. While the nucleophilicity of the bromide ion is expected to be attenuated by association to the HBD, overall rate acceleration is achieved by enhancement of Lewis acidity of the TMSBr reagent through anion abstraction.
Catalytic enantioselective intermolecular desymmetrization of 3-substituted oxetanes
Wang, Zhaobin,Chen, Zhilong,Sun, Jianwei
supporting information, p. 6685 - 6688 (2013/07/26)
Wring it out: The title reaction proceeds in the presence of chiral Bronsted acid catalysts. This efficient ring-opening process features low catalyst loading, mild reaction conditions, broad functional group compatibility, high enantioselectivity, and the capability to generate chiral quaternary centers. The highly functionalized desymmetrization products are versatile chiral building blocks in organic synthesis. Copyright