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

The main group elements
insertion:
- SO'C
SiCI 4 + CH 2 N 2 ----------t Cl,SiCH 2 Cl + N 2
ether
ether
CH2N2
HgCI, + CH,N 2 -------> CICH 2 HgCI -------> CICH 2 HgCH,Cl
-N2 -Nl
R,SnH + N 2 CHC00Et -------> R,SnCH,COOEt + N 2
Replacement of all the M-Cl groups is often difficult or impossible.
Where the reactant is a strong electron-pair acceptor, the formation of
polymethylene is a serious complication. In these cases the initial step involves
coordination of the CH 2 group of diazomethane with the acceptor orbital e.g.
- + - +
X,B + H,C-N= N ----> X,B-CH 2 - N=N
This is followed in fast subsequent steps by elimination of nitrogen and
polymerization. Aluminium compounds usually behave similarly. At low temperatures,
however, dialkylaluminium halides and diazomethane give, initially,
dialkylhalomethylaluminium derivatives, which are stabilized as adducts with
ether.
o
The methylene group can be transferred quantitatively, like a carbene, to
cyclohexene. Norcarane, [ 4.1.0]-bicycloheptane, is formed.
2.6.2 Reaction of aromatic diazonium salts with metal and metalloid
halides or oxides in aqueous solution
This method is applicable to a wide range of heavy metal and metalloid elements.
Two conditions must be fulfilled for it tobe applied successfully. First, as aqueous
media are used, the product must not be susceptible to hydrolysis. This restricts its
use to aryls of Hg, TI and the Group IVB and VB elements. Secondly the element
involved must be susceptible to electrophilic attack by the aryldiazonium ion
ArN;,
The best known and probably the most successful applications are the Bart
reaction for the preparation of arylarsonic acids and the analogous Schmidt
reaction in antimony chemistry,
26
PhN 2 X + M(OH),
alkaline
--~ PhMO(OH) 2 + N 2 + HX (M =As, Sb)
aq. acetone