Convert `D`-glucopyranose to `2,3,4-` triethyl gluocopynoside.

Explanation

First convert `D-`glucose to methyl glucopyranoside with `MeOH//HCl`. Then `overset(6)(C )H_(2)OH` is protected by reacting methyl glucopyranoside with `Ph_(3)C-Cl` (trityl chloride).

only `overset(6)(C )H_(2)OH` is etherified giving `overset(6)(C )H_(2)OCPh_(3)` group. the `2^(@)OH` group. are sterically hindered and do not react with the bulkyl `(Ph_(3)C-Cl)` group.
The free `OH` groups of tritylated methyl glucosides are now methylated with `Me_(2)SO_(4)//NaOH` followed by acidic hydrolysis removes both trityl group and the glycosidic Me group leaving `OMe` group at `C^(2),C^(3)`. and `C^(4)` intact. The hydrolysis of `-OCPh_(3)`, group proceeds by the formation of stable `Ph_(3)C^(o+)` (triphenyl methyl carbocation).