Catalytic ester-amide exchange using group (IV) metal alkoxide-activator complexes.
A process for preparation of amides from unactivated esters and amines has been developed using a catalytic system comprised of group (IV) metal alkoxides in conjunction with additives including 1-hydroxy-7-azabenzotriazole (HOAt). In general, ester-amide exchange proceeds using a variety of structurally diverse esters and amines without azeotropic reflux to remove the alcohol byproduct. Initial mechanistic studies on the Zr(Ot-Bu)4-HOAt system revealed that the active catalyst is a novel, dimeric zirconium complex as determined by X-ray crystallography.
Han
Chong
C
Department of Chemistry and Center for Chemical Methodology and Library Development, Boston University, Boston, Massachusetts 02215, USA.
Lee
Jonathan P
JP
Lobkovsky
Emil
E
Porco
John A
JA
D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D001372:Aza Compounds / Q000494:pharmacology*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004952:Esters / Q000737:chemistry*; D006195:Hafnium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D014025:Titanium / Q000737:chemistry; D014230:Triazoles / Q000494:pharmacology*; D015040:Zirconium / Q000737:chemistry*
D000577:Amides; D001372:Aza Compounds; D004952:Esters; D014230:Triazoles; D015040:Zirconium; D014025:Titanium; C435757:1-hydroxy-7-azabenzotriazole; D006195:Hafnium