B. Rigo et al., REACTION OF TRIMETHYLSILYL BENZHYDRYL ETHERS WITH METHYL N-(TRIMETHYLSILYL)PYROGLUTAMATE - AN EASY AND RAPID N-ALKYLATION, Synlett, (8), 1997, pp. 998
In the presence of a small amount of catalyst (mainly triflic acid), m
ethyl N-(trimethylsilyl)pyroglutamate quickly reacts with benzhydryl c
hlorides or preferentially with trimethylsilyl benzhydryl ethers to gi
ve methyl N-(benzhydryl)pyroglutamates in nearly quantitative isolated
yields.