Synthesis of 1-hydroxypyrazole glycine derivatives

A series of novel α-amino acids containing the 1-hydroxypyrazole ring has been prepared by addition of organomagnesium or organolithium intermediates to diethyl N-Boc-iminomalonate as an electrophilic glycine equivalent. Electrophiles, aryl and heteroaryl substituents were introduced in the pyrazole ring.