Bicyclic Ketals: Versatile Intermediates for the Stereocontrolled Construction of Cyclic Ether Derivatives

All articles of this category The reduction of bicyclic ketal intermediates prepared from readily available chiral ω-ketodiols can serve as a versatile method for the enantioselective construction of cyclic ether derivatives. The reaction proceeds in high stereoselectivity and either cis or trans stereoisomer is accessible by this procedure. The synthetic utility of this method for some natural products containing cyclic ether rings is reviewed. 1. Introduction 2. General Considerations: Bicyclic Ketals 2.1. Preparation of Enantiomerically Pure Bicyclic Ketals 3. Stereoselective Reduction of Bicyclic Ketals 3.1. Stereoselectivity 3.2. Mechanism 3.3. Synthetic Application 3.3.1. Civet Cat Constituent 3.3.2. Isolaurepinnacin Skeleton 3.3.3. Lauthisan 3.4. Stereochemical Prediction by 13 C NMR Spectroscopy 4. Extension 5. Conclusions