Synthesis and hydroamination catalysis with 3-aryl substituted pyrrolyl and dipyrrolylmethane titanium(iv) complexes?

Dalton Transactions Pub Date: 2011-06-06 DOI: 10.1039/C1DT10127G

Abstract

Using an iridium-catalyzed borylation/Suzuki–Miyaura coupling sequence several 3-aryl-pyrroles were accessed; in addition, dipyrrolylmethanes incorporating these 3-arylpyrroles were synthesized. Using the monodentate pyrrolyls, Ti(NMe2)2(HNMe2)(pyr3,5-CF3)2 (1) and a 2,4-diarylpyrrolyl complex Ti(NMe2)3(pyrAr/Ar′) (2) were prepared and structurally characterized. Titanium species bearing the new dipyrrolylmethane ligands Ti(NMe2)2(NHMe2)(dpm3,5-CF3) (3) and Ti(NMe2)2(NHMe2)(dpmF3) (4) were also generated. Kinetics under pseudo-first order conditions with 3 and 4 showed them to be measurably more active than the parent derivative without the electron-withdrawing aryl groups.

Graphical abstract: Synthesis and hydroamination catalysis with 3-aryl substituted pyrrolyl and dipyrrolylmethane titanium(iv) complexes
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