129083-31-4Relevant academic research and scientific papers
Synthesis, structural characterization and catalytic activity of indenyl complexes of ruthenium bearing fluorinated phosphine ligands
Stark, Matthew J.,Shaw, Michael J.,Fadamin, Arghavan,Rath, Nigam P.,Bauer, Eike B.
, p. 41 - 53 (2017)
The synthesis, characterization and catalytic activity of new ruthenium complexes of fluorinated triarylphosphines is described. The new ruthenium complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] were synthesized in 57% and 24% isolated yield, respectively, by thermal ligand exchange of [RuCl(ind)(PPh3)2], where ind = indenyl ligand η5-C9H7?. The electronic and steric properties of the new complexes were studied through analysis of the X-ray structures and through cyclic voltammetry. The new complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] and the known complex [RuCl(ind)(PPh3)2}] differed only slightly in their steric properties, as seen from comparison of bond lengths and angles associated with the ruthenium center. As determined by cyclic voltammetry, the redox potentials of [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] are +0.173 and + 0.370 V vs. Cp2Fe0/+, respectively, which are substantially higher than that of [RuCl(ind)(PPh3)2] (?0.023 V). After activation through chloride abstraction, the new complexes are catalytically active in the etherification of propargylic alcohols (8–24 h at 90 °C in toluene, 1–2 mol% catalyst loading, 29–61% isolated yields). As demonstrated by a comparative study for a test reaction, the three precursor complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}], [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] and [RuCl(ind)(PPh3)2}] differed only slightly in catalytic activity.
Synthesis, Structural Characterization, and Catalytic Activity of Indenyl Tris(N-pyrrolyl)phosphine Complexes of Ruthenium
Stark, Matthew J.,Shaw, Michael J.,Rath, Nigam P.,Bauer, Eike B.
, p. 1093 - 1102 (2016/03/15)
The synthesis, characterization, and catalytic activity of new ruthenium complexes of the tris(N-pyrrolyl)phosphine ligand [P(pyr)3] are described. The new ruthenium complexes [RuCl(ind)(PPh3){P(pyr)3}] and [RuCl(ind){P(pyr)3}2] (ind = indenyl, η5-C9H7-) were synthesized in 73 and 63 % isolated yields, respectively, by thermal ligand exchange of [RuCl(ind)(PPh3)2] with P(pyr)3. The electronic and steric properties of the new complexes were studied through analysis of the X-ray structures and cyclic voltammetry. The new complexes [RuCl(ind)(PPh3){P(pyr)3}] and [RuCl(ind){P(pyr)3}2] and the known complex [RuCl(ind){(PPh3)2}] differed only slightly in their steric properties, as seen from the comparable bond lengths and angles around the ruthenium centers. The oxidation potentials of [RuCl(ind)(PPh3){P(pyr)3}] and [RuCl(ind){P(pyr)3}2] of +0.34 and +0.71 V versus Cp2Fe0/+ (Cp = cyclopentadienyl) are substantially higher than that of [RuCl(ind)(PPh3)2] (-0.023 V), in accordance with the enhanced π-acidity of the P(pyr)3 ligand. The new complexes are catalytically active in the etherification of propargylic alcohols and in the first ruthenium-catalyzed formation of known and new xanthenones from propargylic alcohols and diketones (18 to 72 h at 90 °C in ClCH2CH2Cl or toluene, 1-2 mol-% catalyst, 69-22 % isolated yields).
Ferrocenium hexafluorophosphate as an inexpensive, mild catalyst for the etherification of propargylic alcohols
Queensen, Matthew J.,Rabus, Jordan M.,Bauer, Eike B.
, p. 221 - 229 (2015/08/06)
Commercial ferrocenium hexafluorophosphate ([FeCp2]PF6) was found to be an efficient catalyst for the etherification of terminal, tertiary propargylic alcohols with primary and secondary alcohols (5 h to 3 days reaction time at 40 °C in CH2Cl2, 3 mol% catalyst loading). The propargylic ether products were isolated in 90-20% yields. The alcohols and propargylic alcohols were employed in an equimolar amount and no further additives were required. For a purely aromatic propargylic alcohol, the isolated yields were lower than those for a mixed aromatic-aliphatic propargylic alcohol. Through monitoring reactant consumption and product formation over time, we found that the aromatic propargylic alcohol undergoes yield-diminishing Meyer-Schuster rearrangements to the aldehyde more easily than the mixed aromatic-aliphatic propargylic alcohol. The employment of [Fe(Cp)2]PF6 as a single electron oxidant has the potential to add a new direction in the development of catalysts for the title reaction based on single electron transfer processes.
Etherification reactions of propargylic alcohols catalyzed by a cationic ruthenium allenylidene complex
Alkhaleeli, Doaa F.,Baum, Kevin J.,Rabus, Jordan M.,Bauer, Eike B.
, p. 45 - 48 (2014/02/14)
The cationic ruthenium allenylidene complex RRuR ax-[Ru(indenyl)L(PPh3)CCCPh2] +PF6 catalyzes the etherification of secondary and tertiary propargylic alcohols in a formal nucleophilic substitution reaction utilizing primary and secondary alcohols as the nucleophiles. At a catalyst loading of only 1.1 mol%, the corresponding propargylic ether products were obtained in 9 to 73% isolated yields (18 h reaction time at 100 C); no further additives are required. The reaction exhibits an induction period; as shown by a control reaction, the high reaction temperature may chemically change the allenylidene complex to be employed as the catalyst but does not lead to catalyst deactivation.
Copper-catalyzed borylation of α-alkoxy allenes with bis(pinacolato)diboron: Efficient synthesis of 2-boryl 1,3-butadienes
Semba, Kazuhiko,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
supporting information, p. 12400 - 12403 (2013/12/04)
Something solid to build on: 2-Boryl 1,3-butadienes with various substitution patterns were formed in good to high yields in a copper-catalyzed borylation of α-alkoxy allenes with bis(pinacolato)diboron (see scheme; Bn=benzyl, pin=pinacolate, L is an N-he
