Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• giving a platinum–phosphido complex. Subsequent nucleophilic attack on a Michael acceptor alkene was suggested to lead to a zwitterion intermediate. Addition of a protic additive was beneficial for the selectivity and reaction rate [95]. Several chiral cyclic phosphines were acquired via the lanthanide

• catalyzed intramolecular hydrophosphination of phosphinoalkenes. Scheme 15 shows the diastereoselective synthesis of 2,5-dimethylphospholanes 49 from 47 with a lanthanide catalyst 48 [122]. The common mechanism when using lanthanide [113] or alkaline earth metal [123] catalysts is based on the formation of

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki–Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies

• Jeelani Basha Shaik,
• Venkatachalam Ramkumar,
• Babu Varghese and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2013, 9, 698–704, doi:10.3762/bjoc.9.79

• -metal and lanthanide metal chemistry [1][10][11]. Over the past few years they have gradually replaced the conventional phosphane ligands. The transition-metal complexes of these versatile ligands have been shown to be excellent catalysts for various organic transformations [9][10][11][12][13][14

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• as N-donor ligands toward numerous main-group, transition-metal and lanthanide cations [3]. Coordination compounds LnM(tpy)m (n = 0–4; m = 1,2) ligated with terpyridine derivatives form stable assemblies due to the thermodynamic chelate effect. In the case of transition metal complexes, the σ-donor/π

• provide lanthanide complexes 56 and 57 (Scheme 10). The bromo-derivative 54 was further functionalised by cross-coupling reactions. Namely, the treatment of 54 with aminophenylacetylene in a Sonogashira reaction afforded terpyridine 58. The triple bond was then reduced by hydrogenation providing tpy 59

• . Finally, the hydrolysis of the ester moieties followed by complexation to Eu(III) yielded the lanthanide complex 65 (Scheme 12). This synthetic sequence was used to demonstrate the possibility to prepare labelled oligonucleotides starting from azido-functionalised ones and alkynyl-containing terpyridines

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• −1 for Na+, 0.32 M−1 for K+ and 0.11 M−1 for Li+ in the presence of 10 equiv of the triflate salts. However, those oxacalixarenes form stronger complexes with transition, lanthanide and uranyl cations. Cragg employed the quartz-crystal-microbalance technique to investigate binding by Na+, K+ and Ca2

• Re(CO)3 to two deprotonated phenolic oxygen atoms as shown in Figure 16. Reaction with ester derivative 3k at 85 °C resulted in decomposition of the macrocycle. 4.1.4 Lanthanide complexation: The first study of the binding affinities of lanthanides for oxacalix[3]arenes was in 1995 when Hampton

• also shows that ketone 24 is a weak extracting agent, with a slight preference for Ag+. This is in agreement with the higher basicity of the carbonyl oxygen in the amide group compared with the ketone group. 4.2.4 Lanthanides: Marcos investigated the lanthanide extraction by both 17a [70] and 24 [39

Complete transfer of chirality in an intramolecular, thermal [2 + 2] cycloaddition of allene-ynes to form non-racemic spirooxindoles

• Kay M. Brummond and
• Joshua M. Osbourn

Beilstein J. Org. Chem. 2011, 7, 601–605, doi:10.3762/bjoc.7.70

• oxindoles into chiral non-racemic spirooxindoles containing an alkylidene cyclobutene moiety. The enantiomeric excesses were determined by chiral lanthanide shift NMR analysis and the transfer of chiral information from the allene to the spirooxindole was found to be greater than 95%. Keywords: alkylidene

• cyclobutene; allene; allenyloxindole; chiral lanthanide shift reagent; chiral transfer; Introduction The [2 + 2] cycloaddition reaction of allenes and alkynes provides rapid entry into synthetically challenging alkylidene cyclobutene ring systems. We, along with others, have demonstrated the intramolecular

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

An enantiomerically pure siderophore type ligand for the diastereoselective 1 : 1 complexation of lanthanide(III) ions

• Markus Albrecht,
• Olga Osetska,
• Thomas Abel,
• Gebhard Haberhauer and
• Eva Ziegler

Beilstein J. Org. Chem. 2009, 5, No. 78, doi:10.3762/bjoc.5.78

• should be prototypes for further lanthanide(III) complexes with an enterobactine analogue binding situation. Keywords: CD spectroscopy; enterobactin; lanthanide; macrocycles; molecular modeling; Introduction The availability of metal ions for biological systems is essential for growth and function

• , leading to a bowl-shape structure which is preorganized for the uptake of the metal. Here we present the synthesis of a novel tripodal ligand, which mimics some features of enterobactin, but in contrast is specific for the binding of high coordinated lanthanide(III) ions. The backbone is based on an

• to be tridentate by addition of diethylamide to the 2-position. Recently 2-amido-8-hydoxyquinolines were shown to be good ligands for the 3 : 1 complexation of lanthanide(III)ions [34][35]. The aryl ether of 3 bears already the allylic unit for Claisen rearrangement as well as the chloride leaving

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• of benzaldehyde (1) catalyzed by lanthanide(III)-PyBox complexes was investigated using a T-shaped borosilicate microreactor and electroosmotic flow (Scheme 1) [12]. The reaction was initially screened with different lanthanide (III) complexes such as Ce(III), Yb(III) and Lu(III). Further efforts

Asymmetric aza-Diels- Alder reaction of Danishefsky's diene with imines in a chiral reaction medium

• Bruce Pégot,
• Olivier Nguyen Van Buu,
• Didier Gori and
• Giang Vo-Thanh

Beilstein J. Org. Chem. 2006, 2, No. 18, doi:10.1186/1860-5397-2-18

• ] ZnCl2,[5] or lanthanide triflates[6] and Brönsted acids, including HBF4 or TsOH[7] largely helped promote the reaction. Of late, catalytic asymmetric versions of the aza-Diels-Alder reaction have been explored and high stereoselectivities were reported. So far, a few catalyst systems have been quoted in