Diastereoconvergent Synthesis of trans-5-Hydroxy-6-Substituted-2-Piperidinones by Addition–Cyclization–Deprotection Process
摘要:
A diastereoselective one-pot approach to access trans-5-hydroxy-6-substituted-2-piperidinones by an addition-cyclization-deprotection process has been developed, in which the stereogenic center at the C-6 position was solely controlled by alpha-OTBS group. The utility of this transformation is demonstrated by the asymmetric synthesis of the enantiomer of (-)-CP-99,994.
An efficient enantiocontrolled entry to Martinella alkaloids was achieved based on the unexpected discovery that a catalytic amount of KH/dicyclohexyl-18-crown-6 induced an intramolecular Mukaiyama-Mannich reaction of imine 3, leading to a cascade sequence involving a novel silyl group migration to furnish the pyrroloquinoline core 6.