Unactivated norbornenes in [3+2] cycloadditions: Remarkably stereo-controlled entry into norbornane-fused spirooxindolopyrrolidines,spiro-1,3-indandionolylpyrrolidines,and spirooxindolopyrrolizidines

Abstract

1,3-dipolar cycloaddition reactions of azomethine ylides with unactivated norbornene dipolarophiles and a highly diastereoselective synthesis of the novel norbornane-fused spirooxindolo-pyrrolidines, spiroacenaphthylenolylpyrrolidines, spiro-1,3-indan-dionolylpyrrolidines, and spirooxindolopyrrolizidines having an array of stereocenters are reported. The stereoselective synthesis of spirooxindolopyrrolizidines with eight stereocenters was demonstrated. Single-crystal X-ray structural analyses were performed to unambiguously establish the structure and stereochemistry of the key products.