Neutral and Cationic Zirconium Complexes Bearing Multidentate Aminophenolato Ligands for Hydrophosphination Reactions of Alkenes and Heterocumulenes

Abstract

Zirconium complexes supported by multidentate aminophenolato ligands were synthesized and characterized. The catalytic activities of neutral zirconium complexes and their cationic derivatives in the hydrophosphination of alkenes as well as heterocumulenes have been investigated and compared. Neutral complex 1 bearing a multidentate amino mono(phenolato) ligand exhibited high activity in hydrophosphination of simple alkenes, and anti-Markovnikov products were obtained in 37-94% yields at room temperature. Cationic species generated in situ from complex 3 stabilized by a bis(phenolato) ligand were found to be more active for hydrophosphination of heterocumulenes, i.e., carbodiimides and isocyanates, and gave phosphaguanidines and phosphaureas in 67-93% yields. The Lewis acidity and coordination space of metal centers are modified through changes in the ligand structure, which is found to significantly influence catalytic activity. These complexes are among the most active group 4 metal-based catalysts for hydrophosphination reactions.

Catalyst-free hydrophosphination of alkenes in presence of 2-methyltetrahydrofuran: a green and easy access to a wide range of tertiary phosphines

“…The table displays three examples from the literature using iron or zirconium-based catalysts at room temperature (entries 1-3). [24][25][26] When the reaction was carried out without solvent, we could isolate product 1 with 75% yield. Interestingly, the presence of 2-MeTHF improved the yield and methyl 3-(diphenylphosphine)propanoate was then isolated in 83% yield.…”

Photocatalytic Hydrophosphination with Air-Stable and Commercially Available Bis(acetylacetonato)copper(II) (Cu(acac)2)

“…Hydrophosphination of styrene was examined first due to its common use in recent studies. 41,42,43,44 A chloroform-d1 solution of styrene was treated with 2 equiv. of phenylphosphine in the presence of 5 mol % of 1.…”

Dichiral [4.4.3.01,5]tridecane copper(II) cluster derived from a tripodal ligand having unsymmetrical podands and the linker: Synthesis, structure, surface grafting and catalytic aspects

“…The most recent contribution of bisphenolate armed [4.4.3.0 1,5 ]tridecane metallatranes as reaction mediators includes copolymerization reactions of CO 2 and cyclohexene oxide, polymerization of methacrylate, hydrophosphination of alkenes, alkynes and heterocumulenes, ring-opening polymerization of L-lactic acid, o-carboxy anhydrides and L-lactide, epoxidation, sulfoxidation and catechol oxidation and cycloaddition of epoxides. [12][13][14][15][16][17][18][19][20][21][22][23][24] The metal centres of metallatrane catalysts are widely distributed among various elements, that is, s-block (K), p-block (Al), d-block (Ti, Zr, Zn, Cr, V, Mo, W) and f-block elements (Y, Yb, Nd, La, Sm). Although bisphenolate atranes of Fe(III), Co(III), Cu(II), Si(IV) and Sn(IV) are known; however, their use in catalysis is rarely reported.…”