Solvent-dependent divergent functions of Sc(OTf)₃ in stereoselective epoxide-opening spiroketalizations.
نویسندگان
چکیده
A stereocontrolled synthesis of benzannulated spiroketals has been developed using solvent-dependent Sc(OTf)3-mediated spirocyclizations of exo-glycal epoxides having alcohol side chains. In THF, the reaction proceeds via Lewis acid catalysis under kinetic control with inversion of configuration at the anomeric carbon. In contrast, in CH2Cl2, Brønsted acid catalysis under thermodynamic control leads to retention of configuration. The reactions accommodate a variety of aryl substituents and ring sizes and provide stereochemically diverse spiroketals.
منابع مشابه
Solvent-Dependent Divergent Functions of Sc(OTf)3 in Stereoselective Epoxide-Opening Spiroketalizations
A. Supplementary Figures S1–S2 S2 B. Complete data on spirocyclization of exo-glycal epoxide 6a S3 C. Materials and methods S4 D. Synthesis of propargyl alcohols 2a–h S5 E. Synthesis of exo-glycals 3a–h S8 F. Synthesis of TIPS-protected exo-glycals 4a–h S11 G. Synthesis of 4-substituted exo-glycals 4i–n S14 H. Synthesis of exo-glycal alcohols 5a–n S18 I. Synthesis of exo-glycal epoxides 6a–n S2...
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ورودعنوان ژورنال:
- Organic letters
دوره 16 9 شماره
صفحات -
تاریخ انتشار 2014