title: Palladium complexes with a tridentate PNO ligand. Synthesis of eta1-allyl complexes and cross-coupling reactions promoted by boron compounds.
abstract: The iminophosphine 2-(2-Ph(2)P)C(6)H(4)N=CHC(6)H(4)OH (P-N-OH) reacts with [Pd(mu-Cl)(eta(3)-C(3)H(5))](2) yielding [PdCl(P-N-O)] and propene. In the presence of NEt(3), the reaction of P-N-OH with [Pd(mu-Cl)(eta(3)-1-R(1),3-R(2)C(3)H(3))](2) (R(1) = R(2) = H, Ph; R(1) = H, R(2) = Ph) affords the eta(1)-allyl derivatives [Pd(eta(1)-1-R(1),3-R(2)C(3)H(3))](P-N-O)] (R(1) = R(2) = H: 1; R(1) = H, R(2) = Ph: 2; R(1) = R(2) = Ph: 3). In solution, the complexes 1 and 3 undergo a slow dynamic process which interconverts the bonding site of the allyl ligand. The X-ray structural analysis of 1 indicates a square-planar coordination geometry around the palladium centre with a P,N,O,-tridentate ligand and a sigma bonded allyl group. The complexes [PdR(P-N-O)] (R = C(6)H(4)Me-4, C[triple bond]CPh) react slowly with p-bromoanisole in the presence of p-tolylboronic acid to give [PdBr(P-N-O)] and the coupling product RC(6)H(4)OMe-4. The latter reactions also proceed at a low rate under catalytic conditions. The coupling of allyl bromide with p-tolylboronic acid is catalyzed by [PdCl(P-N-O)]/K(2)CO(3) to give 4-allyltoluene.
authors.affiliation: Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133, Roma, Italy. crociani@stc.uniroma2.it
authors.forename: Bruno
authors.initials: B
authors.lastname: Crociani
authors.forename: Simonetta
authors.initials: S
authors.lastname: Antonaroli
authors.forename: Marcello
authors.initials: M
authors.lastname: Burattini
authors.forename: Paola
authors.initials: P
authors.lastname: Paoli
authors.forename: Patrizia
authors.initials: P
authors.lastname: Rossi