Synthesis and Resolution of Quinazolinone Atropisomeric Phosphine Ligands(,).
The syntheses of 2-methyl-3-[2'-(diphenylphosphino)phenyl]-4(3H)-quinazolinone (MPQ, 1a) and methyl-substituted analogues were achieved in good yield by coupling N-acetylanthranilic acid with the corresponding phosphinoanilines. Resolution of ligand 1bwas achieved using (-)-di-&mgr;-chlorobis[(S)-dimethyl-(1-phenylethyl)aminato-C(2),N]dipalladium(II) (5). The resulting crystalline complex (S,R)-6 served to unambiguously assign the absolute configuration of antipode (R)-(-)-1b. A practical resolution of this series of ligands 1a-c was accomplished using the (benzenesulfonyl)hydrazone derivative of camphorsulfonic acid (7) as a resolving agent.
Dai
Xuedong
X
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139.
Wong
Audrey
A
Virgil
Scott C.
SC