Hydrogen-Bonding Catalysis and Inhibition by Simple Solvents in the Stereoselective Kinetic Epoxide-Opening Spirocyclization of Glycal Epoxides to Form Spiroketals
作者:Jacqueline M. Wurst、Guodong Liu、Derek S. Tan
DOI:10.1021/ja201249c
日期:2011.5.25
hydrogen-bonding catalysis of this reaction to form spiroketal products stereoselectively with inversion of configuration at the anomeric carbon. A series of electronically tuned C1-aryl glycal epoxides was used to study the mechanism of this reaction based on differential reaction rates and inherent preferences for S(N)2 versus S(N)1 reaction manifolds. Hammett analysis of reaction kinetics with these
Stereocontrolled Synthesis of Spiroketals via Ti(O<i>i-</i>Pr)<sub>4</sub>-Mediated Kinetic Spirocyclization of Glycal Epoxides with Retention of Configuration
作者:Sirkka B. Moilanen、Justin S. Potuzak、Derek S. Tan
DOI:10.1021/ja057908f
日期:2006.2.1
stereocontrolled target- and diversity-oriented synthesis of spiroketals. In contrast to most existing methods for spiroketal synthesis, this reaction does not rely upon thermodynamic control over the stereochemical configuration at the anomeric carbon. Stereochemically diverse glycals are first alkylated at the C1-position to introduce a hydroxyl-bearing sidechain, then epoxidized stereoselectively. Treatment with