Table 3.

Data of ¹H (500 MHz, CDCl₃) and ¹³C (125 MHz, CDCl₃) NMR and ¹H–¹H COSY and HMBC correlations for briaviolide M (3).

Position	δH (J in Hz)	δC, Multiple	1H–1H COSY	HMBC
1		46.1, C
2	5.07 d (7.5)	73.0, CH	H2-3	C-1, C-3, C-4, C-15,
				acetate carbonyl
3α/β	2.02 (15.0, 7.5, 5.5); 2.89 dd (15.0, 13.0)	37.7, CH2	H-2, H-4	C-2, C-4, C-5
4	5.08 dd (13.0, 5.5)	73.0, CH	H2-3	C-5, C-6, acetate carbonyl
5		143.7, C
6	5.40 d (9.0)	123.1, CH	H-7	C-4
7	5.57 d (9.0)	73.7, CH	H-6	C-6
8		70.3, C
9	4.98 br s	72.5, CH	n. o. b	C-1, C-7, C-8, C-11, C-17,
				acetate carbonyl
10	2.64 dd (5.0, 1.5)	37.3, CH	H-11	C-1, C-8, C-11
11	2.04 m	42.0, CH	H-10, H-12, H3-20	n. o.
12	4.83 ddd (3.5, 3.0, 3.0)	71.4, CH	H-11, H2-13	n. o.
13α/β	1.94 br d (16.0); 2.09 ddd (16.0, 3.0, 3.0)	25.4, CH2	H-12, H-14	n. o.
14	4.75 dd (3.0, 3.0)	73.9, CH	H2-13	Acetate carbonyl
15	1.23 s	15.4, CH3		C-1, C-10, C-14
16	2.17 s	25.4, CH3		C-4, C-5, C-6
17		64.5, C
18	1.62 s	10.8, CH3		C-8, C-17, C-19
19		170.5, C
20	1.11 d (7.5)	15.0, CH3		C-10, C-11, C-12
OAc-2		170.1, C a
	2.05 s a	21.1, CH3		Acetate carbonyl
OAc-4		170.0, C a
	2.02 s a	21.1, CH3		Acetate carbonyl
OAc-9		168.3, C
	2.24 s	21.4, CH3		Acetate carbonyl
OAc-14		170.0, C a
	2.00 s a	21.1, CH3		Acetate carbonyl
n-OC(O)Pr-12		173.0, C
	2.26 t (7.5)	36.5, CH2	H2-3′	C-1′, C-3′ C-4′
	1.64 sext (7.5)	18.5, CH2	H2-2′, H3-4′	C-1′, C-2′ C-4′
	0.96 t (7.5)	13.7, CH3	H2-3′	C-2′, C-3′

^a data exchangeable; ^b n. o. = not observed.