Page 691 - Advanced Organic Chemistry Part B - Reactions & Synthesis

666 Cerium reagents have also been found to give improved yields in the reaction of
organolithium reagents with carboxylate salts to give ketones.
CHAPTER 7
O
Organometallic
Compounds of Group I (CH ) CO Li 2 equiv CeCl 3
CH (CH ) Li + CH 3 2 4 2 CH (CH ) C(CH ) CH
2 2
3
and II Metals 3 2 2 2 4 3
83%
Ref. 202
Amides, especially of piperidine and morpholine, give good yields of ketones
on reaction with organocerium reagents. 203 It has been suggested that the morpholine
oxygen may interact with the oxyphilic cerium to stabilize the addition intermediate.
R O –
CH 3 Ce 3+
N O

This procedure has been used with good results to prepare certain long-chain ketones
that are precursors of pheromones. 204

O O
CeCl
CH (CH ) CH CHCH 2 CN O + CH (CH ) MgBr 3 CH 3 (CH ) CH CHCH C(CH ) CH 3
2
2 2
2 7
3
3
2 7
2 2
90%
Organocerium reagents also show excellent reactivity toward nitriles and imines, 205
and organocerium compounds were found to be the preferred organometallic reagent
for addition to hydrazones in an enantioselective synthesis of amines. 206
CH 2 OCH 3
CH 2 OCH 3
R′CH 2 CH NN
CeCl 3 ClCO 2 CH 3
RLi RCeCl 2 R′CH 2 CH N N H 2 , Raney Ni R′CH 2 CHNH 2
R CO 2 CH 3 R

General References

E. Erdik, Organozinc Reagents in Organic Synthesis, CRC Press, Boca Raton, Fl, 1996.
P. Knochel and P. Jones, Editors, Organozinc Reagents, Oxford University Press, Oxford, 1999.
R. C. Larock, Organomercury Compounds in Organic Synthesis, Springer-Verlag, Berlin, 1985.
H. G. Richey, Jr., ed., Grignard Reagents; New Developments, Wiley, New York, 2000.
M. Schlosser, ed., Organometallic in Synthesis; A Manual, Wiley, New York, 1994.
G. S. Silverman and P. E. Rakita, eds., Handbook of Grignard Reagents, Marcel Dekker, New York, 1996.
B. J. Wakefield, The Chemistry of Organolithium Compounds, Pergamon Press, Oxford, 1974.
B. J. Wakefield, Organolithium Methods, Academic Press, Orlando, FL, 1988.
B. J. Wakefield, Organomagnesium Methods in Organic Synthesis, Academic Press, London, 1995.
202 Y. Ahn and T. Cohen, Tetrahedron Lett., 35, 203 (1994).
203
M. Kurosu and Y. Kishi, Tetrahedron Lett., 39, 4793 (1998).
204 M. Badioli, R. Ballini, M. Bartolacci, G. Bosica, E. Torregiani, and E. Marcantonio, J. Org. Chem., 67,
8938 (2002).
205 E. Ciganek, J. Org. Chem., 57, 4521 (1992).
206
S. E. Denmark, T. Weber, and D. W. Piotrowski, J. Am. Chem. Soc., 109, 2224 (1987).