Tadao Yoshioka

Specific removal of o-methoxybenzyl protection by DDQ oxidation.

Abstract Methoxybenzyl protecting groups of alcohols were readily and efficiently removed with DDQ in CH2Cl2-H2O at room temperature. Under these neutral conditions, other usual protecting groups, isopropylidene, methoxymethyl, benzyloxymethyl, tetrahydropyranyl, acetyl, t-butyldimethylsilyl, benzyl, benzoyl, and tosyl, as well as functional groups, epoxide, double bond, and ketone, were remained unchanged.

On the selectivity of deprotection of benzyl, mpm (4-methoxybenzyl) and dmpm (3,4-dimethoxybenzyl) protecting groups for hydroxy functions

Abstract The 4-methoxybenzyl (MPM) protecting group for hydroxy functions is readily removed with DDQ in dichloromethane containing a small amount of water at room temperature. Under these neutral conditions, several other protecting and functional groups remained unchanged. 3,4-Dimethoxybenzyl (DMPM) groups are more reactive than MPM groups with DDQ. The benzyl (Bn) protecting group was removed by catalytic hydrogenation over Raney nickel. Selective deprotection of DMPM, MPM and Bn groups is also presented.

Protection of hydroxy groups by intramolecular oxidative formation of methoxybenzylidene acetals with DDQ

Abstract On DDQ oxidation under anhydrous conditions, hydroxy groups located at α or β position to methoxybenzyl ether groups were readily protected by the intramolecular oxidative formation of acid-sensitive methoxybenzylidene acetals, which were further oxidized to alkali-sensitive hydroxy esters in the presence of H 2 O.

DMPM (3,4-dimethoxybenzyl) protecting group for hydroxy function more readily removable than MPM (p-methoxybenzyl) protecting group by DDQ oxidation

Abstract The DMPM (3,4-dimethoxybenzyl) protection for hydroxy function was deprotected more readily than the MPM (p-methoxybenzyl) protection by DDQ oxidation under neutral conditions, and applied to the synthesis of some synthons to macrolide and polyether antibiotics.