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Equilibres conformationnels de glucides au niveau de liaisons σ sp2sp3 CC. IV. Furannoses hybridés sp2 en C(3)

✍ Scribed by J. M. J. Tronchet; Mme F. Barbalat-Rey; J. M. Bourgeois; R. Graf; Mme J. Tronchet

Publisher
John Wiley and Sons
Year
1972
Tongue
German
Weight
575 KB
Volume
55
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

The conformation of 34 branched‐chain unsaturated sugars, prepared by reacting different Wittig reagents with a series of 1,2‐O‐isopropylidene‐furannosul‐3‐oses, has been studied by PMR spectroscopy. The position of each compound in the flexible conformational cycle has been established by using the known stereo‐dependence of the allylic coupling constants and checked with the other parameters of the spectra. An ‘isopropylidenic’ ^4^J~2,4~ coupling constant, present in all compounds whose H—C(4) is endo and absent in their C(4)‐epimers has proved useful for configurational assignment at C(4).

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