Table 1. ¹H and ¹³C NMR Data of Truncatenolide (1)^a and Its Esters (5 and 6)^b.

1				5	6
no.	δCc	δH (J in Hz)	HMBC	δH (J in Hz)	δH (J in Hz)
2	172.7 s		H2C-3, H2C-4, H-10
3	37.3 t	2.42 (1H) md	H2C-4	2.43 (1H) md	2.45 (1H) md
		2.24 (1H) md		2.25 (1H) md	2.26 (1H) md
4	30.2 t	2.42 (1H) md	H-5, H-6, H2C-3	2.43 (1H) md	2.45 (1H) md
		2.24 (1H) md		2.25 (1H) md	2.26 (1H) md
5	130.9 d	5.64 (1H) m	H2C-3, H2C-4	5.72 (1H) m	5.84 (1H) m
6	135.0 d	5.31 (1H) dd (15.4, 8.8)	H2C-4, H2C-8	5.29 (1H) dd (15.4, 8.8)	5.43 (1H) md
7	74.9 d	4.11 td (8.8, 6.6)	H2C-8, H2C-9, H-5	5.17 td (8.8, 6.6)	5.43 (1H) md
8	37.3 t	1.96 (1H) m	H-10, H2C-9	1.95 (1H) m	2.02 (1H) m
		1.61 (1H) md		1.56 (1H) m	1.58 (1H) m
9	31.7 t	1.76 (1H) dd (14.3, 7.7)	CH3	1.79 (1H) m	1.90 (1H) m
		1.61 (1H) md		1.61 (1H) m	1.70 (1H) m
10	72.8 d	4.89 (1H) br quint (6.5)	H2C-8, H2C-9, CH3	4.89 (1H) br quint (6.5)	4.95 (1H) br quint (6.5)
CH3	22.2 q	1.17 (3H) d (6.5)	H-9A	1.18 (3H) d (6.5)	1.20 (3H) d (6.5)
OAc				2.01 (3H) s
2′–6′					7.86 (2H) d (8.3)
3′–5′					7.56 (2H) d (8.3)

^a2D ¹H, ¹H (COSY), and ¹³C, ¹H (HSQC) NMR experiments confirmed the correlations of all of the protons and the corresponding carbons.

^bCoupling constants (J) are given in parentheses.

^cMultiplicities were assigned to the DEPT spectrum.

^dThese two signals are in part overlapped.