Page 628 - Advanced Organic Chemistry Part A - Structure and Mechanisms, 5th ed (2007) - Carey _ Sundberg

610 Scheme 6.2. Alkylation Reactions of Some Organometallic Reagents

CHAPTER 6 A. Organolithium Reagents
Carbanions and Other 1 a Li CH 3
Carbon Nucleophiles + CH 3 I
72%

CH 3 CH 3 CH 3 CH 3
2 b + CH 3 (CH 2 ) 6 CH 2 I
H Li H CH 2 (CH 2 ) 6 CH 3
77 %
OCH 3
OCH 3
3 c TBDMSO Li + BrCH 2 CH C(CH 3 ) 2 TBDMSO CH 2 CH C(CH 3 ) 2
OCH 3 60 %
OCH 3
4 d CH 3 (CH 2 ) 2 C CLi + CH 3 CH 2 Br CH 3 (CH 2 ) 2 C CCH 2 CH 3
65 %
B. Organomagnesium reagents
5 e PhCH 2 MgCl + (C 2 H 5 O) 2 SO 2 PhCH 2 CH 2 CH 3
70%
CH 3
CH 3
6 f CH 3 MgBr + (CH 3 O) 2 SO 2 CH 3 CH 3
CH 3
CH 3 60%
CH 3 CH 3 CH 3 CH 3
MgBr CH 2 CH CH 2
7 g + BrCH 2 CH CH 2
CH 3 CH 3 CH 3 CH 3
79%
a. H. Neumann and D. Seebach, Chem. Ber., 111, 2785 (1978).
b. J. Millon, R. Lorne, and G. Linstrumelle, Synthesis, 434 (1975).
c. T. L. Shih, M. J. Wyvratt, and H. Mrozik, J. Org. Chem., 52, 2029 (1987).
d. A. J. Quillinan and F. Schienman, Org. Synth., 58, 1 (1978).
e. H. Gilman and W. E. Catlin, Org. Synth., I, 360 (1943).
f. L. I. Smith, Org. Synth., II, 360 (1943).
g. J. Eustache, J. M. Bernardon, and B. Shroot, Tetrahedron Lett., 28, 4681 (1987).

at lithium would provide an intermediate structure that could account for the subse-
quent alkylation. This process is represented below for a tetrameric structure, with the
organic group simply represented by C.

C Li C Li
C Li Li C Li C
Li C X Li C Li C
Li C + R'CH2 C X Li
C Li Li
C
R'CH 2 X R'CH 2

In general terms, the reactions of organolithium reagents with alkylating agents
might occur at any of the aggregation stages present in solution and there could be
reactivity differences among them. There has been little detailed mechanistic study
that would distinguish among these possibilities.