[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• was also adopted by Taran in his newer paper [119] but no experimental evidence for this mechanism has been given yet. From previous studies it is known that for the spherically symmetric d10 Cu(I) ion, the common geometries are two-coordinate linear, three-coordinate trigonal planar, and four

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• , connected to a rotatory evaporator as a milling device [99]. Compound 16 displays a higher reactivity than its solvated counterparts, attributed to the coordinatively unsaturated Al centre (i.e., three-coordinate Al). Only in the absence of solvents can this be achieved. Similar studies using group 15

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• . Complex 4 crystallizes in the triclinic space group P-1. The two ligands are also arranged in head-to-tail manner. Each copper ion is three-coordinate in a trigonal planar ligand environment of two nitrogen atoms and one NHC carbon center. The Cu–carbene bond distances are 1.888(6) and 1.899(5) Å which

Copper-catalyzed arylation of alkyl halides with arylaluminum reagents

• Bijay Shrestha and
• Ramesh Giri

Beilstein J. Org. Chem. 2015, 11, 2400–2407, doi:10.3762/bjoc.11.261

• product yields for the current coupling of triarylaluminum reagents with alkyl halides (Table 1). As such, we believe that organoaluminate complexes such as 18, generated from the binding of LiCl to three-coordinate triarylaluminum reagents, are the actual species in solution that undergo transmetalation

Palladium-catalysed cross-coupling reaction of ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole compounds with aryl bromides: A direct protocol for the preparation of unsymmetrical biaryls

• Siphamandla Sithebe and
• Ross S. Robinson

Beilstein J. Org. Chem. 2014, 10, 1107–1113, doi:10.3762/bjoc.10.109

• π-conjugated organic molecules containing a three-coordinate boron moiety such as trimesitylborane (4), arylalkynyldimesitylborane 5 and 2-aryl-1,3-diethyl-1H-benzo[d]1,3,2-diazaborole 6 (Figure 2) are well known and have received considerable attention due to their interesting luminescence

• characteristics, fluoride ion sensing abilities, emissive as well as electron-transporting properties [8][9][10][11]. Three-coordinate boron compounds are electron-poor and strong π-electron acceptors owing to the empty boron pz-orbital, which is capable of significant delocalisation when attached to an organic π

• as NO2, OMe, COMe and diazaborolyl whilst furnishing the coupled product with isolated yields of up to 96% in only 10 minutes. Structures of organoboron compounds 1–3. Structure of π-conjugated three-coordinate organoboron compounds 4 and 5. Synthesis of 2-aryl-1,3-dihydro-1H-benzo[d]-1,3,2

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• , Spain 10.3762/bjoc.9.153 Abstract Although four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated

• organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth

• . Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C–H bond-activation processes. Keywords: C–H bond activation; intermediate; platinum(II); reactive intermediates; three-coordinate; T-shaped; Review