01549nas a2200169   4500008004100000022001400041245015200055210006900207260010600276300001200382490000700394520077900401100002501180700002301205700002401228856012701252       2005                        eng d  a0040-402000aChelation controlled regiospecific O-substitution of myo-inositol orthoesters: convenient access to orthogonally protected myo-inositol derivatives0 aChelation controlled regiospecific Osubstitution of myoinositol   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJAN  a529-5360 v613 a<p>A general method for the completely regioselective protection of the three secondary hydroxyl groups of orthoester derivatives of myo-mositol, utilizing the subtle differences in reactivity exhibited by its alkali metal alkoxides due to differences in their ability to form chelates, is described. This method provides convenient access to orthogonally protected myo-inositol derivatives. A comparison of the methylation of racemic 4-0-trityl-myo-inositol 1,3,5-orthoformate in the presence of sodium or lithium ions showed that stabilization of the C4-alkoxide by chelation with lithium overrides steric hindrance offered by the C6-axial substituent in deciding the regioselectivity during the nucleophilic O-substitution. (C) 2004 Elsevier Ltd. All rights reserved.</p>1 aDevaraj, Subramanian1 aShashidhar, M., S.1 aDixit, Shailesh, S.  uhttps://library.ncl.res.in/content/chelation-controlled-regiospecific-o-substitution-myo-inositol-orthoesters-convenient-0