Table 1.

Data of ¹H (400 MHz, CDCl₃) and ¹³C (100 MHz, CDCl₃) NMR and ¹H–¹H COSY and HMBC correlations for briaviolide K (1).

Position	δH (J in Hz)	δC, Multiple	1H–1H COSY	HMBC
1		46.5, C
2	5.17 d (8.0)	75.4, CH	H2-3	C-1, C-4, C-15, acetate carbonyl
3α/β	1.73 m; 2.62 ddd (15.2, 15,2, 6.0)	32.3, CH2	H-2, H2-4	C-4
4/4′	1.95 m; 2.53 br d (15.2)	28.7, CH2	H2-3	C-5, C-6
5		146.2, C
6	5.29 d (9.2)	117.4, CH	H-7, H3-16	n. o. a
7	5.37 d (9.2)	75.1, CH	H-6	C-5, C-6, C-19
8		70.7, C
9	5.74 d (2.0)	68.0, CH	H-10	C-1, C-7, C-8, C-10, C-11, C-17,
				acetate carbonyl
10	2.34 br s	44.9, CH	H-9	C-1, C-8, C-9, C-15, C-20
11		76.0, C
12	4.85 dd (3.6, 2.4)	75.0, CH	H2-13	n-butyrate carbonyl
13/13′	2.01 m; 2.19 m	24.3, CH2	H-12, H-14	C-12
14	4.56 dd (2.8, 2.8)	74.9, CH	H2-13	C-1, acetate carbonyl
15	1.28 s	14.8, CH3		C-1, C-2, C-10, C-14
16	2.05 br s	27.0, CH3	H-6	C-4, C-5, C-6
17		64.5, C
18	1.70 s	10.2, CH3		C-8, C-17, C-19
19		170.7, C
20	1.29 s	30.0, CH3		C-10, C-11, C-12
OAc-2		170.4, C
	1.98 s	21.5, CH3		Acetate carbonyl
OAc-9		169.4, C
	2.22 s	21.2, CH3		Acetate carbonyl
OAc-14		170.6, C
	2.00 s	21.5, CH3		Acetate carbonyl
n-OC(O)Pr-12		172.6, C
	2.29 t (7.6)	36.4, CH2	H2-3′	C-1′, C-3′, C-4′
	1.65 sext (7.6)	18.3, CH2	H2-2′, H3-4′	C-1′, C-2′, C-4′
	0.95 t (7.6)	13.7, CH3	H2-3′	C-2′, C-3′
OH-11	2.11 s			C-10, C-11, C-12, C-20

^a n. o. = not observed.