_P.-Powell-auth.-Principles-of-Organometallic-Chemistry-Springer-Netherlands-1988

Organotransition metal chemistry
ii) Reaction of an anionic metal complex with an alkyl halide (or related
electrophile e.g. p-toluenesulphonate).
M- +RX--> MR+X-
As most anionic complexes also contain n-acid ligands such as CO, C 5 H 5 or PR 3
this method is most useful in preparing alkyls supported by such groups e.g.
Carbonyl
complexes
Cyclopentadienyl
carbonyls
Nitrogen
bases
Mn(CO); +Mei --> MeMn(CO), + I­
Fe(CO)!- +Mei --> MeFe(CO): + I­
Co(CO): +Mei --> MeCo(C0) 4 + I-
(p.173)
(p. 171)
(p. 178)
CpFe(C0)2- +Mei --> CpFe(C0)2Me + I- (p. 297)
[(dmgH)2Co(pyJr +Mei --> (dmgH)CoMe(py) + I- (p. 232)
(dmgH = dimethylglyoximato)
iii) Addition of an alkyl halide to a coordinatively unsaturated metal complex.
M + RX
ML+ RX
@
1
Co + Mei
L/ ~L
M/
R
~X
M/
R
~X
@
(e. g. Vosko's compound)
1+
Co
t./J "'-Me
The metal complex in these reactions generally behaves as a strong nucleophile.
AII the starting complexes possess a lone pair of electrons in a non-bonding orbita!
centred on the metal. (In some cases, e.g. Vaska's complex and alkyl halides other
than methyl iodide a radical chain mechanism competes successfully with
nucleophilic substitution, SN2.)
iv) Addition of a transition metal hydride to an alkene.
L
~ _/ 1 1
M-H+ C=C ~M-C-C-H
/ -....___ 1 1
This type ofreaction is also observed in Main Group chemistry e.g. hydroboration
(p. 66), hydroalumination (p. 80), hydrostannation (p. 108). It and its reversal
are central to catalytic cycles such as those involved in the hydrogenation
(p. 182) and hydroformylation (p. 387) of alkenes. Hydrozirconation (p. 290)
provides another example of its use in stoichiometric organic synthesis. Its reverse
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