307933-31-9

Upstream product

• 100-42-5 styrene 
• 829-84-5 dicyclohexylphosphane 
• 103-63-9 1-phenyl-2-bromoethane 

Downstream Products

• 577969-98-3 (p-cymene)Ru(PCy₂CH₂CH₂C₆H₅)Cl₂ 

Relevant academic research and scientific papers

Heteroleptic alkyl and amide iminoanilide alkaline earth and divalent rare earth complexes for the catalysis of hydrophosphination and (Cyclo) hydroamination reactions

[{N^N}M(X)(thf)n] alkyl (X=CH(SiMe3)2) and amide (X=N(SiMe3)2) complexes of alkaline earths (M=Ca, Sr, Ba) and divalent rare earths (YbII and EuII) bearing an iminoanilide ligand ({N^N}-) are presented. Remarkably, these complexes proved to be kinetically stable in solution. X-ray diffraction studies allowed us to establish size-structure trends. Except for one case of oxidation with [{N^N}YbII{N(SiMe3)2}(thf)], all these complexes are stable under the catalytic conditions and constitute effective precatalysts for the cyclohydroamination of terminal aminoalkenes and the intermolecular hydroamination and intermolecular hydrophosphination of activated alkenes. Metals with equal sizes across alkaline earth and rare earth families display almost identical apparent catalytic activity and selectivity. Hydrocarbyl complexes are much better catalyst precursors than their amido analogues. In the case of cyclohydroamination, the apparent activity decreases with metal size: Ca>Sr>Ba, and the kinetic rate law agrees with R CHA=k[precatalyst]1[aminoalkene]1. The intermolecular hydroamination and hydrophosphination of styrene are anti-Markovnikov regiospecific. In both cases, the apparent activity increases with the ionic radius (CaHA=k[styrene]1[amine]1[precatalyst] 1 and RHP=k[styrene]1[HPPh2] 0[precatalyst]1, respectively. Mechanisms compatible with the rate laws and kinetic isotopic effects are proposed. [{N^N}Ba{N(SiMe 3)2}(thf)2] (3) and [{N^N}Ba{CH(SiMe 3)2}(thf)2] (10) are the first efficient Ba-based precatalysts for intermolecular hydroamination and hydrophosphination, and display activity values that are above those reported so far. The potential of the precatalysts for C-N and C-P bond formation is detailed and a rare cyclohydroamination-intermolecular hydroamination "domino" sequence is presented. Activated alkenes: Long sought heteroleptic alkyl and amide complexes of large alkaline earths (Ca, Sr, Ba) and divalent rare earths (Yb, Eu) supported by a bulky iminoanilide ancillary ligand have been prepared (see figure). These complexes are very versatile, active, and selective in the catalysis of the cyclohydroamination of aminoalkenes, and the intermolecular hydroamination and hydrophosphination of activated alkenes. Copyright

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(SiMe3)2](THF) (1Yb, 1-4Ca) coordinated by amidine-amidopyridinate ligands L1-4 were synthesized via a transamination reaction between proligands L1-4H and bisamido complexes M[N(SiMe3)2]2(THF)2 (M = Yb, Ca). The reactions of Yb[N(SiMe3)2]2(THF)2 with proligands L2H-L4H containing CF3 and C6H4F 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 (PhPH2, 2,4,6-Me3C6H2PH2, 2-C5NH4PH2, Ph2PH, Cy2PH). Complexes 1Yb, 1-4Ca performed high catalytic activities in styrene hydrophosphination with PhPH2 and Ph2PH and demonstrated high regioselectivity affording exclusively the anti-Markovnikov addition products. For primary PhPH2 the reactions (1:1 molar ratio of substrates) catalyzed by 1Yb, 1Ca, and 2Ca proved to be highly chemoselective affording the secondary phosphine Ph(PhCH2CH2)PH; however, complexes 3Ca and 4Ca led to the formation of both secondary and tertiary phosphines in 80:20 and 86:14 ratios. Styrene hydrophosphinations with 2,4,6-Me3C6H2PH2 and 2-pyridylphosphine for all complexes 1Yb and 1-4Ca proceeded much more slowly compared to PhPH2. Addition of 2-C5NH4PH2 to styrene catalyzed by complex 1Yb turned out to be non-regioselective and led to the formation of a mixture of Markovnikov and anti-Markovnikov addition products, while all Ca complexes enabled regioselective anti-Markovnikov addition. Complexes 1Ca and 1Yb containing catalytic centers featuring similar ionic radii performed different catalytic activity: the ytterbium analogue proved to be a more active catalyst for intermolecular hydrophosphination of styrene with Cy2PH, 2-C5NH4PH2, and PhPH2, but less active with sterically demanding 2,4,6-Me3C6H2PH2. Styrenes containing in p-position electron-donating groups (Me, tBu, OMe) performed with noticeably lower rates in the reactions with PhPH2 compared to styrene. Complexes 1Yb, 1Ca, 2Ca, 3Ca, and 4Ca enabled addition of PhPH2 toward the double C-C bond of α-Me-styrene, and the reaction rate for this substrate is noticeably lower; however quantitative conversions were reached in -40 h. Complexes 1Ca and 2Ca promoted 1,2-addition of PhPH2 to 2,3-dimethyl butadiene with excellent regio- and chemoselectivity to afford linear secondary phosphines. Hydrophosphination of inert 1-nonene with Ph2PH with 40% conversion becomes possible due to the application of complex 2Ca (40 h, 70 °C). The rate law for the hydrophosphination of styrene with Ph2PH catalyzed by 1Ca was found to agree with the idealized equation: v = k[styrene]1[1Ca]1.

When bigger is better: Intermolecular hydrofunctionalizations of activated alkenes catalyzed by heteroleptic alkaline earth complexes

New alkaline-earth amido complexes catalyze the regioselective intermolecular hydroamination (see scheme; Ae=alkaline earth) and hydrophosphination of styrene and isoprene with unprecedented activities. The catalytic performances increased linearly with the size of the metal. Copyright

CsOH-promoted P-alkylation: A convenient and highly efficient synthesis of tertiary phosphines

A mild and efficient method for the synthesis of tertiary phosphines and ditertiary phosphines has been developed. In the presence of cesium hydroxide, molecular sieves and DMF at room temperature, various secondary phosphines and alkyl bromides were examined, and the results have demonstrated that this methodology offers a general synthetic procedure to produce tertiary phosphines in moderate to high yields. Optically active tertiary phosphine synthesis is also described.