Highly Enantio‐ and Diastereoselective Inverse Electron Demand Hetero‐Diels–Alder Reaction using 2‐Alkenoylpyridine <i>N</i>‐Oxides as <i>Oxo</i>‐Heterodienes

Abstract

Abstract A general catalytic inverse electron demand hetero‐Diels Alder reaction for 2‐alkenoylpyridine N ‐oxides is presented. 2‐Alkenoylpyridine N ‐oxides react very efficiently with alkenes in the presence of bisoxazolidine‐copper(II) [BOX‐Cu(II)] complexes to give chiral dihydropyrans bearing a pyridine ring at the 6‐position with very high yields and excellent diastereo‐ and enantioselectivity. These heterodienes exhibited higher reactivity and enantioselectivity than the corresponding non‐oxidized 2‐alkenoylpyridines.