Micro Water-Initiated and Cu(OTf)2-Catalyzed Oxygen Transfer-Insertion-Mannich-Type Reaction of α-Carbonyl Diazos with Benzo-N,O-acetals.

A novel and efficient method to access (1,2b)-syn-2-hydroxy-1-aryl-2-tetrahydroisoquinolin propan-1-ones (±)-3a-3n and (±)-4a-4v has been developed through a micro water-initiated and Cu(OTf)2-catalyzed process from benzo-N,O-acetals and α-diazo ketones. A series of substituted (1,2b)-syn-2-hydroxy-1-aryl-2-tetrahydroisoquinolin propan-1-ones were obtained with moderate to excellent yields and excellent selectivities (syn:anti >19:1). In addition, density functional theory (DFT) calculations were performed to explain the stereochemistry outcome for this novel transformation.