Bis(trichloromethyl) Carbonate

Selective Cleavage of N-Benzyl-Protected Secondary Amines by Triphosgene

“…In connection with efforts to develop synthetic routes to the marine natural product haliclonacyclamine A (1) 1 and its various congeners, 1,2 we sought a method that would allow for selective mono-debenzylation of the readily available bis-piperidine 2. 3 Among the various reagents investigated for this purpose, 4 the commercially available and easily handled triphosgene [bis(trichloromethyl) carbonate] 5,6 proved especially efficacious in converting, in a completely selective fashion, substrate 2 into the carbamoyl chloride 3, which could be readily manipulated so as to give the corresponding secondary amine or a now orthogonally protected diamine. In view of this result, and the likely utility of regioselective methods for the N-debenzylation of amines, 4c we have evaluated the capacity of triphosgene to effect the selective cleavage of a suite of N-benzyl-protected secondary amines and report the outcomes here.…”