Directing the Regioselectivity of the Alkylation of Pyroglutamate Carbamates by Formation of a Stable Counter-ion Complex
作者:Christian V. Stevens、Thomas Rammeloo、Norbert De Kimpe
DOI:10.1055/s-2001-17457
日期:——
The alkylation of benzyl N-Boc pyroglutamate was carried out using chloroformates in order to introduce an activating group at the 4-position. Deprotonation with three equivalents of LiHMDS followed by alkylation with different electrophiles lead to 2-alkylated pyroglutamates. The directing effect of the alkylation to the 2-position can be accounted for by the formation of a counterion complex.