Igc. Coutts et al., REMARKABLE SELECTIVITY IN THE REACTION OF 1-TRITYL-I-LITHIOIMIDAZOLESWITH T-BUTYL HALOGENOACETATES, Journal of heterocyclic chemistry, 31(4), 1994, pp. 857-860
2-Lithio-1-triphenylinethylimidazoles react with t-butyl halogenoaceta
tes to give a variety of products, the nature of which is cleanly dete
rmined by the halogen atom. With chloroacetate the products are chloro
methyl ketones, while bromacetate gives di-t-butyl imidazolesuccinates
, and iodoacetate yields iodoimidazoles. In each case 50% of the paren
t triphenylmethylimidazole is recovered from the reaction. When the tr
iphenylmethyl substituent is replaced by the N,N-dimethylsulfamoyl gro
up, reaction with bromoacetate is suppressed, but t-butyl chloroacetat
e and iodoacetate again give chloroketones and aryl iodides respective
ly.