NMR data of compound 2^a.

Position	2a		2b
	δ C,b type	δ H (J in Hz)	δ C,b type	δ H (J in Hz)
1/1′	179.1, C		179.1, C
2/2′	158.6, C		158.6, C
3/3′	n.d.c		n.d.c
4/4′	188.3, C		188.3, C
5/5′	145.5, C		145.5, C
6/6′	139.1, C		139.1, C
7/7′	152.1, C		152.1, C
8/8′	102.0, CH	7.21, s	102.0, CH	7.20, s
9/9′	127.1, C		127.1, C
10/10′	112.2, C		112.2, C
11/11′	119.2, C		119.2, C
12/12′	42.9, CH2	3.12, s	42.9, CH2	3.10, s
13/13′	171.4, C		171.4, C
14/14′	24.6, CH3	1.91, s	24.6, CH3	1.88, s
15/15′	61.2, CH3	4.13, s	61.2, CH3	4.12, s
OH-5/OH-5′		12.06, s	12.06, s

^aMeasured in CDCl₃ (¹H at 600 MHz and ¹³C at 150 MHz).

^bData were extracted from the HSQC and HMBC spectra.

^cn.d. = not detected.