RING SIZE AND CONFORMATION OF SOME (5R)-5-C-ALKYL-5-C-PHENYL-D-XYLOSE DERIVATIVES

Some pyranose and furanose derivatives of 6-deoxy-5-C-phenyl-L-idose and (5R)-5-C-cyclohexyl-5-C-phenyl-D-xylose are described. The limitations of the Karplus equation as an approach to assessing the preferred conformation of furanoses are discussed. 6-Deoxy-5-C-phenvl-L-idose forms pyranose and furanose derivatives but (5R)-5-C-cyclohexyl-5-C-phenyl-D-xylose forms only furanose derivatives.