Tetrahedron report number 163

https://kops.uni-konstanz.de/bitstream/handle/123456789/10014/2000_CoordChemRev_203_325_Mecking.pdf;sequence=1

Cationic nickel and palladium complexes with bidentate ligands for the CC linkage of olefins

Publisher Summary The chemistry of metal–alkynyl compounds is developing at a rapid pace. The bonds of alkynyl ligands, like those of organic alkynes have been shown to participate in a rich set of chemical transformations. Electronic-absorption band maxima and extinction coefficients have been reported for a large number of metal–alkynyl complexes. Casual comparisons of electronic-absorption band energies or intensities among a series of compounds in the absence of such experiments are not without the risk of misinterpretation because a variety of important effects not associated with the presence or absence of M-CCR π-bonding may be operative such as mixings between electronic states of identical symmetry but different orbital character. The best and simplest means of placing the M–C bond distances of metal–alkyl complexes in a context that allows insight into whether or not they manifest M-CCR π-interactions is to compare them to M–C bond distances of complexes where such effects are expected to be insignificant, as for metal–alkynyl compounds.

The Bonding of Metal-Alkynyl Complexes

Development of an Air-Stable Nickel Precatalyst for the Amination of Aryl Chlorides, Sulfamates, Mesylates, and Triflates

The synthesis and characterization of the air-stable nickel(II) complex trans-(PCy2Ph)2Ni(o-tolyl)Cl is described in conjunction with an investigation of its use for the Mizoroki–Heck-type, room temperature, internally selective coupling of substituted benzyl chlorides with terminal alkenes. This reaction, which employs a terminal alkene as an alkenylmetal equivalent, provides rapid, convergent access to substituted allylbenzene derivatives in high yield and with regioselectivity greater than 95:5 in nearly all cases. The reaction is operationally simple, can be carried out on the benchtop with no purification or degassing of solvents or reagents, and requires no exclusion of air or water during setup. Synthesis of the precatalyst is accomplished through a straightforward procedure that employs inexpensive, commercially available reagents, requires no purification steps, and proceeds in high yield.

/pdf/simplifying-nickel-0-catalysis-an-air-stable-nickel-5bj16gjuio.pdf

J. Chatt

Papers

345. Alkyls and aryls of transition metals. Part III. Nickel(II) derivatives