“…2a: Liquid; 1 H NMR (400 MHz, CDCl 3 ) δ 4.99 (s, 1H), 4.76 (s, 1H), 4.24−4.16 (m, 1H), 2.11−1.92 (m, 3H), 1.49−1.39 (m, 2H), 1.38−1.20 (m, 7H), 0.87 (t, J = 6.6 Hz, 3H); 13 C NMR (CDCl 3 , 100 MHz) δ 153.5, 107.8, 70.8, 31.7, 31.6, 27.7, 22.5, 22.1, 14.0; MS ( m / z ) 142 (M + , 1.35), 71 (100); IR (neat, cm -1 ) 3361, 2930, 2861, 1647, 1458.…”