Copper‐catalyzed domino reaction between terminal alkynes, isocyanates, and oxiranes: An atom‐economic route to morpholine derivatives

Abstract

In situ generated copper acetylides react with isocyanates and oxiranes to form a decent range of morpholine derivatives. The reactions proceeded with acceptable yields and excellent regioselectivity. The presence of oxygen and moisture completely inhibited the reaction. The scope of the reaction is wide and the reactions involve consecutive C-C, C-N, and C-O bond formations. CDCl 3 ): δ H = 0.98 (9 H, s, 3 Me), 3.89 (1 H, dd, 2 J = 13.9 Hz, 3 J = 5.4 Hz, CH), 4.14 (1 H, dd, 2 J = 13.9 Hz, 3 J = 10.7 Hz, CH), 4.39 (1 H, dd, 3 J = 10.7, 5.4 Hz, CH), 6.54 (1 H, s, CH), 6.94 (1 H, t, 3 J = 7.6 Hz, CH), 7.31 (2 H, t, 3 J = 7.6 Hz, 2 CH), 7.35 (1 H, t, 3 J = 7.3 Hz, CH), 7.44 (2 H, t, 3 J = 7.3 Hz, 2 CH), 7.64 (2 H, d, 3 J = 7.3 Hz, 2 CH), 7.82 (2 H, d, 3 J = 7.6 Hz, 2 CH). 13 C NMR (125.7 MHz, CDCl 3 ):