The Quercitols or Cyclohexanepentols

Ten diastereoisomers (four meso and six active) are predicted for a quercitol or deoxyinositol. All ten are now known, although some of the individual enantiomorphs are missing (see Table I). 

Although proto-quercitol was isolated from botanical sources in 1849, and wbo-quercitoP in 1904, the configurations were not established until 1932, and 1950, respectively.  

Four synthetic diastereoisomers cis, epi, neo, and scyllo) were pre-pared during the period 1941-58. Finally, the alio, gala, and talo diastereomers were synthesized in 1961 in Japan and in California, and the last remaining (muco) isomer by the Japanese group in the same year. 

As yet, only the (+)-pro o and -)-vibo stereoisomers of quercitol have been found in Nature. The name quercitol ( oak sugar ) was well chosen, since proto-quercitol (IS) is present in all of 33 species of the genus Quercus examined, and it seems to be present in every part of the tree. Nineteen plant species from eight other botanical families also contain profo-querci-tol.  

Levorotatory yf6o-quercitol (30) is present in Viburnum tinus L. and in at least three other botanical genera.  

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