Stereoselective synthesis of 5-alkyliden-6-aminotetrahydro-2-pyranones through an unexpected isomerization of the hydroxytetrahydro-2-pyridinones obtained by the selective reduction of acylated enaminones

Article abstract of DOI:10.1016/S0040-4020(97)10333-7

A convenient methodology for the stem selective preparation of 5- alkyliden-6-aminotetrahydro-2-pyranone 4 is reported. The synthesis of 2- pyranone 4 occurs through an unknown isomerization mechanism of the hydroxytetrahydro-2-pyridinone 3 an accessible starting material obtained by mild and selective reduction of the 5-acyltetrahydro-2-pyridinone 2. The isomerization mechanism and the stereoselectivity in the synthesis of 2- pyranone 4 was investigated and rationalized.