Carbasugars motif

Strictly speaking, the basic motif of a carbasugar possesses a carbohydrate counterpart, be it a real molecule or only hypothetically obtainable. To be precise, the carba counterpart of a monosaccharide arises from the replacement of the hemiacetal ring oxygen in carbohydrates by a carbon atom (usually a CH2), leaving the rest of the structure and chirality intact. In literature, however, this distinction does not appear to be so clear and often polyhydroxylated carbocyclic... 

It was then postulated and soon recognised that carbasugars, by virtue of their close resemblance to parent monosaccharides, could possess interesting biological activities. Therefore, after McCasland s pioneering work, there has been extreme interest in the synthesis of carbasugars and, in particular, of carbapyranoid motifs. 

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