1,1'-Disubstituted 4-pyridinyl and 5-pyrimidinyl ferrocenes were prepd. by mech. induced solid-state Suzuki coupling reactions of 1,1'-ferrocenediboronic acid. Reaction of [h5-C5H4B(OH)2]2Fe with ArBr in the presence of 10-20% of PdCl2(dppf) and KOH or KF on Al2O3 support as a base gave [h5-C5H4B(OH)2](h5-C5H4Ar)Fe (2, 3; Ar = 4-pyridinyl, 5-pyrimidinyl), (h5-C5H4Ar)2Fe (4, 5) and mixed-ligand complex (h5-C5H4Ar1)(h5-C5H4Ar2)Fe (6, Ar1 = 4-pyridinyl, Ar2 = 5-pyrimidinyl). The reaction was initiated by grinding the palladium catalyst with KF/Al2O3 or KOH/Al2O3 and adding a few drops of MeOH together with the reactants. It is shown that the solvent-free process is much faster, and more selective, than the same reaction carried out in soln. Crystal structure of 6 is reported.
Mechanically Induced Expeditious and Selective Preparation of Disubstituted Pyridine/Pyrimidine Ferrocenyl Complexes.
BRAGA, DARIO;D'ADDARIO, DANIELA;POLITO, MARCO;GREPIONI, FABRIZIA
2004
Abstract
1,1'-Disubstituted 4-pyridinyl and 5-pyrimidinyl ferrocenes were prepd. by mech. induced solid-state Suzuki coupling reactions of 1,1'-ferrocenediboronic acid. Reaction of [h5-C5H4B(OH)2]2Fe with ArBr in the presence of 10-20% of PdCl2(dppf) and KOH or KF on Al2O3 support as a base gave [h5-C5H4B(OH)2](h5-C5H4Ar)Fe (2, 3; Ar = 4-pyridinyl, 5-pyrimidinyl), (h5-C5H4Ar)2Fe (4, 5) and mixed-ligand complex (h5-C5H4Ar1)(h5-C5H4Ar2)Fe (6, Ar1 = 4-pyridinyl, Ar2 = 5-pyrimidinyl). The reaction was initiated by grinding the palladium catalyst with KF/Al2O3 or KOH/Al2O3 and adding a few drops of MeOH together with the reactants. It is shown that the solvent-free process is much faster, and more selective, than the same reaction carried out in soln. Crystal structure of 6 is reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
