| Abstract
| - Organophosphorus esters 9, 10, 14, and 15 prepared via reaction of diethyl- and diphenylphosphorylchloride, di(o-tolyl)phosphinyl chloride, and 2,8-dimethylphenoxaphosphinyl chloride with HOAtare excellent coupling reagents for peptide synthesis which are generally superior to their uronium/guanidinium analogues and HOBt- or HODhbt-derived phosphate ester counterparts in minimizingloss of configuration during segment coupling. The phosphinyl analogues are more shelf-stablethan the phosphoryl systems. The new reagents have been tested in segment couplings leading totwo tripeptides (20, 21) and a hexapeptide 22. Outstanding utility is also shown for the solid-phase assembly of the ACP decapeptide. Similar results were obtained with the 2- and 4-nitro-and 2,4-dinitrophenylsulfonyl esters derived from HOAt.
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