Hydroxymethyl conformation from coupling constants - monosaccharides

The experimental values of the 3JH5,H6 [1] are interpreted using two different sets of limiting values.
The values of Bock and Duus [1] are based on the Karplus equation of Haasnoot et al. [2] whereas those of Stenutz et al. [3] are based on quantum mechanical calculations in 2-hydroxymethyl tetrahydropyran (oxane). Apart from slight differences in the relationship between torsion angles and coupling constants Stenutz et al. assume a larger torsion (65°) for the gg and gt rotamers.
The θ torsion is defined here as C5-C6-O6-X, i.e. H or glycosyl/alkyl. The amount of trans can be estimated from 2JH6R,H6S if the amounts of the ω rotamers are known.
The ω rotamers are estimated to be accurate to about +-5%, but the error in θ is larger since 1) the relationship between 2JH6R,H6S is less reliable and 2) the ω rotamer populations are required. An error of at least +-10% is to be expected.
[1] K. Bock and J.Ø. Duus, J. Carbohydr. Chem. 13 (1994) 513-543
[2] C.A.G. Haasnoot, F.A.A.M. DeLeeuw and C. Altona, Tetrahedron 36 (1980) 2783-2792.
[3] R. Stenutz, I. Carmichael, G. Widmalm and A.S. Serianni, J. Org. Chem. 67 (2002) 949-958 DOI 10.1021/jo010985i
Hydroxymethyl coupling constants and rotamer distribution in hexopyranoses
Coupling constants Bock & Duus Stenutz et al.
Compound 3JH5,H6R 3JH5,H6S 2JH6R,H6S Pgt Pgg Ptg Pgt Pgg Ptg θtrans
methyl α-D-glucopyranoside5.492.39-12.355057-74742107
methyl α-D-glucopyranoside (CD3OD)5.642.40-11.805156-749411126
methyl β-D-glucopyranoside6.112.47-12.315650-65435119
α-D-glucopyranose (DMSO)5.002.30-11.204563-842481046
β-D-glucopyranose (DMSO)5.902.20-11.805555-105339827
methyl α-D-mannopyranoside6.402.44-12.205948-757321112
methyl 2-acetamido-2-deoxy-β-D-glucopyranoside5.382.35-12.204959-846441013
methyl 6-O-acetyl-β-D-glucopyranoside4.902.30-12.304464-84149109
methyl 4,6-di-O-acetyl-β-D-glucopyranoside3.802.10-12.603476-10306280
methyl 6-O-phosphono-α-D-glucopyranoside (pH 1.3)4.602.40-11.604166-737521132
methyl 6-O-phosphonato-α-D-glucopyranoside (pH 9.3)3.531.91-12.133280-122867617
methyl 4-deoxy-α-D-xylo-hexopyranoside6.203.03-12.065445152311714
methyl 4-deoxy-β-D-xylo-hexopyranoside7.423.34-12.046531465152014
methyl 4-O-acetyl-β-D-glucopyranoside5.902.20-12.305555-105339810
methyl 4,4-di-hydroxy-α-D-xylo-hexopyranoside8.402.40-12.008028-879111019
methyl 4-thio-α-D-glucopyranoside5.002.00-12.504765-12445064
methyl 4-ammonio-4-deoxy-α-D-glucopyranoside (pH 2.0)4.643.70-12.44345610324325-1
methyl 4-amino-4-deoxy-α-D-glucopyranoside (pH 9.0)5.402.46-12.424858-64643115
C-propyl β-D-glucopyranoside8.502.408127-8811010
methyl α-D-galactopyranoside8.603.70-11.70751697602424
methyl β-D-galactopyranoside7.504.83-11.765819245953617