Relative reactivity of hydroxyl groups in inositol derivatives: role of metal ion chelation.
O-Alkylation of myo-inositol derivatives containing more than one hydroxyl group via their alkali metal alkoxides (sodium or lithium) preferentially occurs at a hydroxyl group having a vicinal cis-oxygen atom. In general the observed selectivity is relatively higher for lithium alkoxides than for the corresponding sodium alkoxide. The observed regioselectivity is also dependent on other factors such as the solvent and reaction temperature. A perusal of the results presented in this article as well as those available in the literature suggests that chelation of metal ions by inositol derivatives plays a significant role in the observed regioselectivity. Steric factors associated with the axial or equatorial disposition of the reacting hydroxyl groups do not contribute much to the outcome of these O-alkylation reactions. These results could serve as guidelines in planning synthetic strategies involving other carbohydrates and their derivatives.
Devaraj
Subramanian
S
Division of Organic Chemistry, National Chemical Laboratory, Pashan Road, Pune, Maharashatra 411 008, India.
Jagdhane
Rajendra C
RC
Shashidhar
Mysore S
MS
D000478:Alkylation; D002614:Chelating Agents / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D007294:Inositol / Q000031:analogs & derivatives* / Q000737:chemistry; D008672:Metals, Alkali / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity
D002614:Chelating Agents; D006878:Hydroxides; D008672:Metals, Alkali; D009942:Organometallic Compounds; D017670:Sodium Compounds; C046771:butyllithium; C524957:sodium hydride; D007294:Inositol; C031356:hydroxide ion