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

Zinc. cadmium and mercury
oxiranes or alkyl halides. Mineral acids cleave both bonds in R 2 Hg, but carboxylic
acids only one; aryl-mercury bonds react more readily than alkyl-mercury, in
spite of their greater strength.
Trihalomethylmercury derivatives ha ve been developed, largely by D. Seyferth,
as sources of dihalocarbenes. They are prepared by reactions of the type
PhHgBr + HCCI,
KOBu'
------> PhHgCBrCI 2
benzene
A cyclopropane is formed in the presence of an alkene.
O + PhHgCBrCl2
benzene/
80°C
An iodomethyl derivative, prepared as follows, provides an alternative to the
Simmons-Smith reagent.
PhCH2Hgl
CH 2N2/
ether, THF
0°C
PhCH2 HgCH21
The reaction between a mercury compound and chloroform in the presence of
a base, mentioned above, is an example of a common type, in which a somewhat
acidic C-H bond is mercurated.
"'-c-H + HgX
~ "'-C-HgX
/ 2 ~ / '
-H\
o
""-C-Hg-C/
/ "'---
With most metals, the reaction would proceed in the reverse direction (e.g.
cleavage of organozinc derivatives by acid, HX). Carbon compounds which react
in this way include alkynes, ketones and cyclopentadiene.
Hc==cH
2RHgCL/
olcoholic KOH
RHgC==CHgR
ilHg(N03>2,Hg0
H3CCOCH 3 ------ H3 CCOCH2 Hgi
CoS04
ii) KI
o
ilHg(OCOCF 3 J 2
Ph2 C=CH2 -ii-l -N 0 - 8 -,----. Ph 2C=CHHgBr
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