Diels-Alder reactions of dihydropyridinones: synthetic entry to the manzamine A tricyclic core

摘要: For the construction of tricyclic core manzamine A (1), Diels-Alder reactions some dihydropyridinones were surveyed. The N-protecting group dihydropyridinone played an important role in achieving a successful reaction. In view its electron-withdrawing character as well thermal stability, p-toluenesulfonyl protecting was found to be best our synthesis. An effective method for preparation 3-alkyldihydropyridinones via Michael addition dehydroalanine derivatives has also been devised