Gold‐ and Silver‐Catalyzed [4+2] Cycloadditions of Ynamides with Oxetanes and Azetidines

Abstract

Abstract Gold‐catalyzed [4+2] cycloadditions between ynamides and oxetanes are described; these reactions involve oxetanes and gold‐π‐ynamides as nucleophiles and electrophiles, respectively. Excellent cycloaddition regioselectivities are achieved over a reasonable range of ynamide and oxetane substrates. For azetidines, their [4+2] cycloadditions with ynamides are implemented more efficiently with silver hexafluoroantimonate, which is also compatible with various ynamides and azetidines. These two cycloadditions provide facile accesses to six‐membered heterocycles such as 6‐amino‐3,4‐dihydro‐2 H ‐pyrans and 2‐amino‐1,4,5,6‐tetrahydropyridines. magnified image