Ketal-lactone compounds and their stereoselective cleavage to cyclic ethers
The easy preparation of ketal-lactone compounds via Diels-Alder reaction, followed by hydrolysis and cyclization and excellent stereoselective ring opening of the ketal-lactone to 6-membered and 7- membered cyclic ethers are described.
Diastereoselective Construction of 2,2,6-Trisubstituted Tetrahydropyrans by Intramolecular Alkylation Reaction of Lithiium Enolates Generated from α-Alkoxy Carboxylates
The intramolecular alkylation reaction of enolates of t-butyl α-alkoxy carboxylates in THF-HMPA proceeded stereoselectively to afford 2,2,6-trisubstituted tetrahydropyrans with high cis-selectivity.
STEREOSELECTIVE REDUCTION OF ACETALS. A METHOD FOR REDUCTIVE GENERATION OF HETEROCYCLIC RING SYSTEMS
A new synthetic process for the construction of oxygen-containing heterocyclic systems starting from bicyclic acetals is described.We have investigated the mechanism and the stereochemical course of the reductive cleavage of acetals.