ABSTRACT
The carbonyl ene reaction of 2-methylenetetrahydropyrans provides a rapid, high yielding route for the preparation of ß-hydroxydihydropyrans under mild conditions. This process provides a new entry for the synthesis of 2-substituted tetrahydropyrans and for the direct introduction of oxygen heterocycles into molecular frameworks.
Subject(s)
Pyrans/chemistry , Pyrans/chemical synthesis , Aldehydes/chemistry , Catalysis , Chlorides/chemistry , Combinatorial Chemistry Techniques , Cyclization , Ketones/chemistry , Molecular Structure , Oxygen/chemistry , Stereoisomerism , Zinc Compounds/chemistryABSTRACT
Three component coupling of a 2-methylenetetrahydropyran, an activated aldehyde or ketone and a secondary nucleophile provides an efficient preparation of tetrahydropyranyl ketides, a unit common to many complex natural products.
Subject(s)
Macrolides/chemical synthesis , Pyrans/chemistry , Aldehydes/chemistry , Ketones/chemistry , Macrolides/chemistry , Spiro Compounds , StereoisomerismABSTRACT
An approach to the macrocyclic core of phomactin A is described. Central to this strategy is the use of a cis-fused oxadecalin intermediate, prepared using the dihydropyrone Diels-Alder reaction. The conformational bias inherent to this system is then used to facilitate macrocycle formation via an intramolecular B-alkyl Suzuki coupling.
