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

Organotransition metal chemistry
several ways. Oxidation by cerium(IV) probably gives a 17 -electron radical cation
initially, which then rearranges by alkyl migration to an acyl derivative.
I Ce 4 + +· MeOH -:;:::-0
Fpl +Rl ....!-cpFe(COl 2 R -[CpFe(COl 2 R] -+[CpFe(CO)(CORJ]"t"-- RC
;:CL, ;i:r
"OMo
FpCL+ RHgCL
FpBr+RBr
Attack by carbon nucleophiles such as enolates on Fp( alkene) + is not at all
regioselective. The propene complex reacts readily with the dimethyl malonate
ion, but a mixture of isomeric products is formed.
ty 3 of pro duct)
(2f3 of product)
Lithium alkyls or Grignard reagents generally reduce the alkene complex to Fp 2 •
This problem can sometimes be overcome by using LiCuR 2 instead.
The addition of carbon nucleophiles is probably irreversible and kinetically
controlled. Amines and alcohols, however, add reversibly and the thermodynamically
more stable product is obtained selectively. A novel synthesis of {3-
lactams involves attack by a primary amine followed by oxidation.
R
Pb0
h
R'NH
Fp
2
-----.,-+
or a1r
( migratory insertion of CO) p-tactam
Greatly improved regioselectivity is observed when the alkene ligand has
electron-withdrawing substituents. Vinyl ether complexes, prepared from rx.­
bromoacetals, are attacked exclusively at the carbon atom which bears the
RO(<OR RO(<OR OR
NaFp/ HBF4Et 20/
R' THF R' CH 2 CL 2
=r< + ROH
+ R'
Br Fp -7e•c Fp
OEt
OEt
Nur-<
CHzCLz
acetone
+Fpl
H8F4'Etz()/ dNu
Na!/ dNu
1+
THF,-78°C
Fp Nu
1+
Fp
-7e•c Fp
d
242