Table 5.

Comparison of calculated (in vacuo) vs experimental (in CDCl₃) ¹³C NMR chemical shifts of stereoisomers 1a–d.

		1a		1b		1c		1d
carbon	δexp	δcalcd	|Δδ|a, ppm	δcalcd	|Δδ|a, ppm	δcalcd	|Δδ|a, ppm	δcalcd	|Δδ|a, ppm
9	24.0	21.6	2.4	26.0	2.0	27.5	3.5	22.1	1.9
8	73.6	72.4	1.2	74.6	0.9	73.0	0.6	70.7	2.9
7	75.6	76.1	0.5	71.3	4.3	79.1	3.5	76.4	0.8
6	35.6	36.0	0.3	37.3	1.7	34.2	1.4	34.0	1.6
5	36.2	39.2	3.1	36.9	0.8	37.4	1.2	36.8	0.6
4	89.6	87.1	2.5	87.1	2.5	88.8	0.8	87.4	2.2
13	30.9	30.3	0.5	28.0	2.9	32.3	1.4	32.7	1.8
15	25.3	24.2	1.0	22.6	2.7	20.4	4.8	24.5	0.8
16	10.7	9.6	1.1	11.1	0.4	11.7	1.0	10.2	0.5
MAEb			1.4		2.0		2.0		1.5
DP4c			62.9		1.9		5.4		29.7

^a|Δδ| = |δ_exp − δ_calcd|, absolute differences for experimental versus calculated ¹³C NMR chemical shifts. ^bMAE = Σ[|δ_exp − δ_calcd|]/n. ^cDP4 probabilities were obtained considering all the calculated chemical shifts, as proposed by Smith and Goodman [28].