Highly Active Ethene Polymerization Catalysts with Unusual Imine Ligands - Late Transition Metal Polymerization Catalysis - page 63

Scheme 3.2 Synthesis of N-aminopyrroles 9 - 16 (Me=methyl, i-Pr= isopropyl, Ph=phenyl,
t -Bu= t -butyl, o -Tol = ortho -tolyl).
dure. In contrast to the reported protocol which uses rather exotic protecting
groups [Cl 3 CCH 2 OC(O), Me 3 SiCH 2 CH 2 OC(O)] [20], we used the more common
protecting group benzyloxycarbonyl or acetyl, respectively. In terms of yield of
products the benzyloxycarbonyl group ( 1 - 4 : 66-89% yield) is preferred over the
acetyl group ( 5 - 6 : 37-53% yield), but in the following deprotection step the acetyl
moiety is easier to cleave off.