355012-35-0Relevant academic research and scientific papers
Highly efficient monophosphine platinum catalysts for alkyne diboration
Thomas,Souza,Marder
, p. 1650 - 1656 (2001)
Automated parallel screening using a series of in situ generated platinum(0) phosphine complexes has allowed the identification of improved catalysts for the diboration of alkynes using bis(pinacolato)diboron (B2(pin)2, pin = OCMe2CMe2O). A selection of phosphines were added to [Pt(NBE)3] (NBE = norbornene), which contains only labile mono-olefin ligands, and the activity of the resulting solutions as catalysts for the diboration of 4-CF3C6H4C≡CC6H 4CF3-4′ 1 by B2(pin)2 was investigated by in situ GC-MS and/or NMR spectroscopy. This allowed the optimum phosphine : platinum stoichiometry to be identified as 1 : 1, and the large differences in catalyst activity depending on the nature of the phosphine to be quantified. The best phosphines employed in the study, PCy3 and PPh2(o-Tol) (o-Tol = C6H4Me-o), give activities orders of magnitude greater than the worst, such as P(C6F5)3 and PBut3. The monophosphine catalysts function much more efficiently than previous catalysts for a range of alkynes allowing diborations to be performed at ambient temperatures. The diboration of strained cyclic alkenes and some vinyl- and allyl-arenes proceeded well, although the catalysts were inactive for other olefinic systems examined. As a result of these studies, the isolable and stable compound [Pt(PCy3)(η2-C2H4) 2] was identified as an excellent catalyst for alkyne diboration even at room temperature.
Synthesis and reactivity of cobalt boryl complexes
Adams, Christopher J.,Baber, R. Angharad,Batsanov, Andrei S.,Bramham, George,Charmant, Jonathan P.H.,Haddow, Mairi F.,Howard, Judith A.K.,Lam, Wai Han,Lin, Zhenyang,Marder, Todd B.,Norman, Nicholas C.,Orpen, A. Guy
, p. 1370 - 1373 (2006)
The synthesis and reactivity of phosphine-cobalt boryls, were investigated. The reactivity studies have shown that alkyne diboration takes place and borylation of aryl bromides is possible with low selectivity. Boryl transfer was investigated initially by
Palladium-catalyzed double cross-coupling reaction of 1,2- bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls: Annulative approach to functionalized polycyclic aromatic hydrocarbons
Shimizu, Masaki,Nagao, Ikuhiro,Tomioka, Yosuke,Kadowaki, Tsugumi,Hiyama, Tamejiro
experimental part, p. 8014 - 8026 (2011/11/05)
This study demonstrates that the double cross-coupling reaction of 1,2-bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls proceeds smoothly with the aid of a catalytic amount of Pd(PPh3) 4 in the presence of excess base to give a variety of polycyclic aromatic hydrocarbons, such as phenanthrenes, [5]helicene, dithienobenzenes, triphenylenes, dibenzo[g,p]chrysenes, and triphenyleno[1,2-b:4,3-b′] dithiophenes in good to high yields. It is noteworthy that the annulations using 2,2′-dibromooctafluorobiphenyl as an electrophile furnish the otherwise difficult to synthesize octafluorophenanthrenes and semi-fluorinated dibenzo[g,p]chrysenes in high yields.
