Tetraisopropyldisiloxanyl, or TIPDS, is an important protective group that was created specifically for polyhydroxy substances like sugar. TIPDS can shield two alcohol groups of a molecule.
a. The isopropyl groups around the Si atoms hinder the TIPDS group slightly. Which OH of 1-methoxy-α-D-arabinofuranose has a higher chance of reacting with TIPDS chloride first? Draw the product with one oxygen attached to the TIPDS group.
b. The next oxygen nearest to it is reached once the TIPDS group has been connected to the first oxygen. Draw the final product with TIPDS attached to two oxygens.
c. Now that the oxygens are shielded, the unprotected hydroxy group can undergo reactions. Draw the final product result of treating the protected 1-methoxy-α-D-arabinofuranose from (b) with tosyl chloride, pyridine, and then NaBr.
