Carbon–Carbon Bond Formation at a Neutral Terminal Carbido Ligand: Generation of Cyclopropenylidene and Vinylidene Complexes

Abstract

Eine C1‐Quelle, der Carbidkomplex [Ru(C)(PCy3)2Cl2] (1) addiert glatt an Dimethylacetylendicarboxylat (DMAD) zum Cyclopropenylidenkomplex 2 (rot O, grün Cl, gelb P, grau C). Diese Produktbildung ist überraschend angesichts der Instabilität des trans‐Cyclopropyliden‐Analogons. HX‐Reagentien bewirken 1,1‐Addition und Ringöffnung unter Bildung von Vinylidenkomplexen wie 3, die die Ringöffnungsmetathesepolymerisation von Norbornen katalysieren.

Planar Four‐Coordinate Boron: A Single, Flat Boron Atom as a Ligand for Four Metals

“…This concept has thus underpinned the discovery of compounds with planar four-coordinate carbon atoms (A-D, Figure 1). [6][7][8] While research into transitionmetal complexes featuring carbido ligands (a single carbon atom) has been sustained, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and in many cases compounds containing planar carbon involve a certain degree of metalation of the carbon atom, examples containing four metalcarbon bonds to the central atom are still exceedingly rare (for example, complex A, Figure 1). [6] Of the theoretical studies on planar tetracoordinate firstrow main-group elements, only Schleyer and co-workers considered boron analogues.…”