Ring structures Pyranose, Septanose

Fig. 1. Higher-order sugars L-g/yceroD-manno-Heptose (1, open-chain and 2, a-pyranose) and A -acetylneurami ilic acid (3, a-pyranose form). Structures 4-8 depict D-glucose (4) as its open-chain Fischer projection, and as the a-oxetose (5), a-furanose (6), a-pyranose (7), and a-septanose (8) ring forms.

V. A. Danilova, N. V. Istomina, and L. B. Krivdin, 13C-13C Spin-spin coupling constants in structural studies XXXVII. Rotational conformations of hydroxy groups in pyranose, furanose, and septanose rings, Russ. J. Org. Chem., 40 (2004) 1194-1199. 

While the pyranose and furanose ring forms of the sugars dominate the carbohydrate literature, the uncommon septanose ring forms have long intrigued sugar chemists, with particularly notable contributions by Stevens in Australia. The chapter in this volume from Saha and Peczuh (Storrs, Connecticut) provides a comprehensive overview of the subject from both the synthetic and structural viewpoints and presents a detailed analysis of the conformational behavior of these ring forms. It may be noted... 

Several new papers have been published by Krivdin and co-workers on non-empirical calculations of carbon-carbon couplings across one bond. They include a reference data set and a practical guide for structural elucidation of saturated carbocycles, studies on monocyclic alkanes, nine classical caged polycycloalkanes such as, for example, adamantane and diamantane, bicyclobutane-containing polycycloalkanes, aliphatic and alicyclic oximes, and studies on rotational conformations of hydroxyl groups in pyranose, furanose and septanose rings. ... 

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