Trichloroacetamidate method

C. Gallo-Rodriguez, L. Gandolfi, andR. M. de Lederkremer, Synthesis of /j-D-Gal /-(l-3)-D-GlcNAc by the trichloroacetamidate method and of / -D-Gal/-(l-6)-D-GlcNAc by SnCL -promoted glycosyla-tion, Org. Lett., 1 (1999) 245-247. 

Synthesis of Tetra- and Higher Saccharides.- Cellotetraose has been synthesized using the trichloroacetamidate method the adopted procedures involved the use of the trisaccharide derivative (64)... 

N,N-Diethyl-l,2,2-trichlorovinylamine has been prepared by the action of trimethyl, triethyl, or triisopropyl phosphite or triphenylphosphine on N,N-diethyl-2,2,2-trichloroacetamide., These methods require a reaction temperature of 150-160° and several distillations in order to obtain a pure product. Consequently, the yields of the vinylamine are lower than by the present procedure.3... 

Yamamoto, N., Isobe, M. Direct preparation of guanidine from trichloroacetamide. A potentially important method to (-)-tetrodotoxin. Chem. Lett. 1994, 2299-2302. 

Allerhand and Gutowsky (1964) have re-examined AA-dimethyl-trichloroacetamide by the independent spin-echo method. They obtain activation parameters which are not in good agreement with previous studies or with steady-state spectral studies repeated in this work for the same molecule. The spin-echo method yields parameters Ea= 14-6+ 0 6kcal-1 and log A = 12-5+ 0-4 compared with Ea= 9-9 + 0-3 kcal mole-1 and log A = 9-1 + 0-2 obtained by Rogers and Woodbury (1962). 

Under some circumstances, it is possible to effect removal of amide groups by selective hydride reduction. Trichloroacetamides are readily cleaved by sodium borohydride in alcohols. Another reductive method that can be applied to ben-zamides, and probably to other simple amides, involves treatment with diisobutylaluminum hydride. At low temperatures, this reduction stops at the carbinolamine stage. Hydrolysis then yields the amine. 

Sodium acyloxyborohydride has been found to effect the reduction of aliphatic and aromatic nitriles to the corresponding amines any chloro, nitro, or aromatic substituents remain unaffected under the reaction conditions. Full details have appeared of the [3,3]sigmatropic rearrangement of trichloroacetamidic esters of allylic alcohols, which provides a superior method for the 1,3-transposition of amino (and hydroxy) functions (Scheme 2). 

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