Application of substituted 2-(trimethylsilyl)ethyl esters to suppress diketopiperazine formation

摘要

The use of differently substituted 2-(trimethylsilyl)ethyl esters for C-terminal protection in peptide synthesis has been investigated. While the use of the unsubstituted 2-(trimethylsilyl)ethyl ester resulted in a substantial amount of diketopiperazine at the dipeptide stage, use of the corresponding methyl-substituted silyl ester gave a significant reduction of this undesired pathway. Both esters could be deprotected by fluoride-induced cleavage under mild conditions.