Amido Ca and Yb(II) Complexes Coordinated by Amidine-Amidopyridinate Ligands for Catalytic Intermolecular Olefin Hydrophosphination.

A series of amido Ca and Yb(II) complexes LM[N(SiMe)](THF) (1Yb, 1-4Ca) coordinated by amidine-amidopyridinate ligands L were synthesized via a transamination reaction between proligands LH and bisamido complexes M[N(SiMe)](THF) (M = Yb, Ca). The reactions of Yb[N(SiMe)](THF) with proligands LH-LH containing CF and CHF fragments do not allow for preparing the target Yb(II) complexes, while the Ca analogues were synthesized in good yields. Complexes 1Yb and 1-4Ca were evaluated as precatalysts for hydrophosphination of styrene, p-substituted styrenes, α-Me-styrene, and 2,3-dimethylbutadiene with various primary and secondary phosphines (PhPH, 2,4,6-MeCHPH, 2-CNHPH, PhPH, CyPH).

Bis(alkyl) rare-earth complexes coordinated by bulky tridentate amidinate ligands bearing pendant PhP[double bond, length as m-dash]O and PhP[double bond, length as m-dash]NR groups. Synthesis, structures and catalytic activity in stereospecific isoprene polymerization.

A series of new tridentate amidines 2-[PhP[double bond, length as m-dash]X]CHNHC(tBu)[double bond, length as m-dash]N(2,6-RCH) (X = O, R = iPr (1); X = S, R = Me (2); X = NPh, R = Me (3); X = N(2,6-MeCH), R = Me (4)) bearing various types of donor PhP[double bond, length as m-dash]X groups in a pendant chain was synthesized. Bis(alkyl) complexes {2-[PhP[double bond, length as m-dash]X]CHNC(tBu)N(2,6-RCH)}Ln(CHSiMe) (Ln = Y, X = O, R = iPr (5); Ln = Er, X = O, R = iPr (6); Ln = Lu, X = O, R = iPr (7); Ln = Y, X = NPh, R = Me (8); Ln = Lu, X = NPh, R = Me (9); Ln = Lu, X = N(2,6-MeCH), R = Me (10)) were prepared using alkane elimination reactions of 1, 3 and 4 with Ln(CHSiMe)(THF) (Ln = Y, Er, Lu) in toluene and were isolated in 45 (5), 62 (6), 56 (7), 65 (8), 60 (9), and 60 (10) % yields respectively. The X-ray diffraction studies showed that complexes 6-8 are solvent free and feature intramolecular coordination of the P[double bond, length as m-dash]X (X = O, NPh) group to the lanthanide ions.

Tandem C(sp(2))-OMe Activation/C(sp(2))-C(sp(2)) Coupling in Early Transition-Metal Complexes: Aromatic C-O Activation beyond Late Transition Metals.

We report on combined structural, kinetic, and computational studies unraveling the mechanism of a unique, highly selective intramolecular C(sp(2))-OMe cleavage/C(sp(2))-C(sp(2)) coupling tandem reaction in group 3 metal (Y and Sc) complexes of amidine-amidopyridinate ligands. The latter process represents a rare stoichiometric model of the nonredox cleavage of inert C(sp(2))-O bonds relevant to cross-coupling reactions of aromatic ethers catalyzed by late transition metals.