An extremely mild method for amide-cleavage by using the triazine-based benzylating reagent 4-(4,6-diphenoxy-1,3,5-triazin-2-yl)-4-benzylmorpholinium trifluoromethanesulfonate (DPT-BM), which spontaneously releases benzyl cation species when being dissolved at room temperature, has been developed. O-Benzylation of the amide with DPT-BM and the subsequent hydrolysis of the resulting intermediate benzyl imidate salt afford the corresponding amine and benzyl ester, which can be converted by hydrogenolysis into a carboxylic acid under neutral conditions. O-Benzylation proceeds depending on both steric and electronic factors around the amide group. Thus, some amides have been selectively cleaved over other amides. Furthermore, intramolecular chemoselective cleavage of an amide group in the presence of an ester group was achieved. Such selective hydrolytic reactions cannot be performed with Meerwein reagents as well as under acidic or basic hydrolytic conditions.

A new O-benzylating reagent, that is, 4-(4,6-diphenoxy-1,3,5-triazin-2-yl)-4-benzylmorpholinium trifluoromethanesulfonate (DPT-BM), has been developed. Benzyl cation equivalents are generated from DPT-BM by dissolving the compound in a solvent at room temperature under non-acidic conditions. The benzylation of various alcohols by using a combination of DPT-BM and magnesium oxide provided the benzyl ethers in good yields.

No abstract

New Approach to Oligotriazoles Using a Cobalt Complex of Propargyl Azides as a Synthetic Component. -The target compounds are prepared by repetitive sequence involving a 1,3-dipolar cycloaddition of alkynes with alkyne-cobalt complexes and subsequent oxidative deprotection. The cobalt complex serves as activating group for the Nicholas reaction to give substrates (III) and as protection for the alkyne moiety. In case of chiral substrate (X), the chain extension proceeds without racemization. -(TSUKADA, Y.; YAMADA, K.; KUNISHIMA*, M.; Tetrahedron Lett. 52 (2011) 26, 3358-3360, http://dx.

Temperature. -Benzyl cations are generated from the novel reagent (I) by solvation in a suitable solvent under non-acidic conditions. The reagent is a non-hygroscopic, stable solid, which can be stored in a refrigerator up to six months and handled under normal laboratory conditions. -(YAMADA, K.; TSUKADA, Y.; KARUO, Y.; KITAMURA, M.; KUNISHIMA*, M.; Chem. -Eur.