“…13 C-NMR (101 MHz, CDCl 3 ) δ 169.3, 168.4, 157.9, 151.8, 138.3, 138.0, 137.9, 137.3, 135.9, 134.8, 130.2, 129.9, 129.8, 129.3, 129.2, 128.6, 128.5, 128.4, 126.9, 120.7, 120.2, 110.6, 67.2, 51.7, 28.7, and 21.0. MS (IE, 70 eV) m/z](%): 568 (M + -NH-t-butyl, 0.1); 540 (40); 345 (71); 316 (33); 196 (54); 121 (100); 91 (39); 77 (22); and 57 (14). HRMS (ESI+): calculated for.…”