Alkoxy Exchange Strategy for the Synthesis of N,N'-Dimethylated (Alkoxy)triazinediones as Solid Reagents for Acid-Catalyzed O-Alkylation.

N,N'-Dimethylated (alkoxy)triazinediones (DMATs-R) with eight different O-alkyl groups (R), such as benzyl, allyl, and tert-butyl groups, were synthesized in 61-94% yield through the alkoxy exchange reaction of DMAT-Me with the corresponding alcohol. Molecular sieves were added to the reaction mixture to shift the alkoxy exchange equilibrium toward the product via the absorptive removal of the methanol formed in situ. All the DMATs-R were obtained as stable solids, in contrast to previously reported N,N'-diallyl analogs that included oil compounds. The treatment of alcohols with DMATs-R in the presence of an acid catalyst afforded the corresponding alkyl ethers in up to 92% yield. A base-labile bromoalkyl group is compatible with these reactions. The O-tert-butylation of a sterically hindered tert-alcohol with DMAT-tBu yielded the di-tert-butyl ether product. The DMATs-R are suitable reagents for the O-alkylative protection of alcohols under nonbasic conditions.