Homolytic base-promoted aromatic alkylations by alkylmercury halides

Article abstract of DOI:10.1021/ja971809n

Electron transfer chain reactions leading to substitution in electronegatively substituted benzene derivatives can be observed with alkylmercury halides in the presence of proton accepters such as DABCO. Promotion by base involves the abstraction of a proton from the substituted cyclohexadienyl adduct radical to form a radical anion which readily transfers an electron to RHgX with the regeneration of R^.. Aromatic substitutions involving t-Bu^. are highly regioselective and yield products of only para attack for PhCHO, PhCOCH₃, PhCOCMe₃, PhCOPh, PhCN, phthalimides, or 1,2-dicyanobenzene. The ortho/para substitution products are observed for isophthaldehyde or 1,3-dicyanobenzene, while 1,4-dicyanobenzene yields the ortho substitution product. At 25-35°C substitution by t-Bu^. ortho to an ester group is not observed and m- or p-cyanobenzoate esters yield only products of substitution ortho to the cyano group. With the isopropyl radical substitution ortho to the ester function is observed with diethyl isophthalate. Intramolecular radical cyclizations of the radical adducts of 1-aryl-4-penten-1-ones leading to α-tetralones is also promoted by the presence of DABCO. When the aryl group contains a para ester function, spirocyclizatien occurs leading to a rearrangement acyl radical which can be oxidized by t-BuHgCl to the acyl cation and the carboxylic acid.

Full text of DOI:10.1021/ja971809n

J. Am. Chem. Soc. 1997, 119, 8795-8801
8795
Homolytic Base-Promoted Aromatic Alkylations by
Alkylmercury Halides1
Glen A. Russell,* Ping Chen, Byeong Hyo Kim, and Ragine Rajaratnam
Contribution from the Department of Chemistry, Iowa State UniVersity, Ames, Iowa 50011
ReceiVed June 2, 1997X
Abstract: Electron transfer chain reactions leading to substitution in electronegatively substituted benzene derivatives
can be observed with alkylmercury halides in the presence of proton acceptors such as DABCO. Promotion by base
involves the abstraction of a proton from the substituted cyclohexadienyl adduct radical to form a radical anion
which readily transfers an electron to RHgX with the regeneration of R•. Aromatic substitutions involving t-Bu• are
highly regioselective and yield products of only para attack for PhCHO, PhCOCH3, PhCOCMe3, PhCOPh, PhCN,
phthalimides, or 1,2-dicyanobenzene. The ortho/para substitution products are observed for isophthaldehyde or 1,3-
dicyanobenzene, while 1,4-dicyanobenzene yields the ortho substitution product. At 25-35 °C substitution by t-Bu•
ortho to an ester group is not observed and m- or p-cyanobenzoate esters yield only products of substitution ortho
to the cyano group. With the isopropyl radical substitution ortho to the ester function is observed with diethyl
isophthalate. Intramolecular radical cyclizations of the radical adducts of 1-aryl-4-penten-1-ones leading to R-tetralones
is also promoted by the presence of DABCO. When the aryl group contains a para ester function, spirocyclization
occurs leading to a rearrangement acyl radical which can be oxidized by t-BuHgCl to the acyl cation and the carboxylic
acid.
Introduction
Scheme 1
Scheme 2
Bases, such as 1,4-diazabicyclo[2.2.2]octane (DABCO), can
promote the oxidative (substitutive) homolytic reactions of
alkylmercury halides with unsaturated compounds when the
adduct radicals possess acidic hydrogen atoms, Scheme 1.2,3
Previously reported examples of alkylations occurring by
Scheme 1 include coumarin,4 maleimide,5 acyclic 1,4-enedi-
ones,6 1,4-naphthoquinone,4 furmaronitrile,7 2-substitution in
benzothiazole and benzimidazole,8 and intramolecular cycliza-
tions leading to R-tetralones.4,9
It appeared to us that bimolecular aromatic homolytic
substitutions should proceed by a similar mechanism involving
X Abstract published in AdVance ACS Abstracts, August 15, 1997.
(1) Electron Transfer Processes. Part 64.
1 and 2 provided the substituent Z in Scheme 2 can stabilize
the radical adduct 1 and the radical anion 2.10,12 Herein we
describe such processes occurring in the photolysis of t-BuHgX
with benzaldehyde, phenones, phthalimides and other disubsti-
tuted benzenes as well as further examples of homolytic
cyclizations leading to R-tetralones.
(2) Promotion of electron transfer by deprotonation of a radical was
originally described in the radical chain degradation of diazonium ions in
CH3OH (CH2dO•- + ArN2+ f CH2dO + ArN2 ): Bunnett, J. F.; Wamser,
•
C. C. J. Am. Chem. Soc. 1967, 84, 6712. Bunnett, J. F.; Takayama, H. J.
Am. Chem. Soc. 1968, 90, 5173. Another early example was the formulation
of the homolytic conversion of p-nitrobenzyl chloride to the stilbene:
Russell, G. A.; Pecoraro, J. M. J. Am. Chem. Soc. 1979, 101, 3331. With
R ) p-O2NC6H4 the reaction involves
-8 RCH2
-8
-Cl
RCHCl:
•
RCH2Cl•-
(10) Loss of a proton from a dihydropyridine radical cation is a key
step in the oxidative homolytic alkylation of pyridinium ions in aqueous or
Me2SO solutions.11 It has also been suggested that Bu3SnH,3 or I-, can
serve as a proton acceptor in homolytic cyclization reactions of N-(ω-
iodoalkyl)pyridinium salts: Murphy, J. A.; Sherburn, M. S. Tetrahedron
Lett. 1990, 31, 1625, 3495. Murphy, J. A.; Sherburn, M. S.; Dickinson, J.
M.; Goodman, M. J. Chem. Soc., Chem. Commun. 1990, 1069.
(11) (a) Minisci, F.; Vismara, E.; Fontana, F.; Morini, G.; Serravalle,
M.; Giordano, C. J. Org. Chem. 1987, 52, 730. (b) Russell, G. A.;
Rajaratnam, R.; Wang, L.; Shi, B. Z.; Kim, B. H.; Yao, C. F. J. Am. Chem.
Soc. 1993, 115, 10596.
RCH2CH(Cl)R•-
-8 RCH2CHR•
+8
-Cl
-H
RCHdCHR•- RCH2Cl8 RCHdCHR + RCH2Cl•-
(3) Another example of promotion of electron transfer by loss of a proton
is the SRN1-type process in cyclizations of aryl radicals with an o-(CH2)n-
NHC(S)R side chain (attack of Ar• upon S; n ) 0, 1; R ) Me, Ph) in the
presence of AlBN and DABCO or Bu3SnH. It is suggested that Bu3SnH
can also serve as a proton acceptor in these processes: Bowman, W. R.;
Heaney, H.; Jordon, B. M. Tetrahedron 1991, 47, 10119.
(4) Russell, G. A.; Kim, B. H.; Kulkarni, S. V. J. Org. Chem. 1989, 54,
3768.
(12) It has been suggested that at 160 °C, Bu3SnH can remove a proton
from the cyclohexadienyl radical formed by cyclization of PhN(Me)-
•
COCMe2 : Beckwith, A. L. J.; Storey, J. M. D. J. Chem. Soc., Chem.
(5) Russell, G. A.; Kim, B. H. Synlett 1990, 87.
Commun. 1995, 977. A more likely example is proton abstraction by Bu3-
(6) Russell, G. A., Kim, B. H. Tetrahedron Lett. 1990, 31, 6273.
(7) Russell, G. A.; Chen, P.; Yao, C.-F.; Kim, B. H. J. Am. Chem. Soc.
1995, 117, 5967.
(8) Russell, G. A.; Wang, L.; Rajaratnam, R. J. Org. Chem., in press.
(9) Russell, G. A.; Kulkarni, S. V.; Khanna, R. J. Org. Chem. 1990, 55,
1080.
SnH in refluxing toluene from the cyclohexadienyl radical formed by 1,6-
cyclization of o-C6H4 N(Me)COAr and the sulfur analog.3 One of the first
•
examples of oxidative cyclization employing Bu3SnH, and possibly involv-
ing proton abstraction, was the uninitiated 1,6-cyclization of N-(p-tosyl)-
R-(halomethyl)piperidines at 22 °C: Koehler, J. J.; Speckamp, W. N.
Tetrahedron Lett. 1977, 631, 635.
S0002-7863(97)01809-X CCC: $14.00 © 1997 American Chemical Society

8796 J. Am. Chem. Soc., Vol. 119, No. 38, 1997
Russell et al.
Scheme 3
formed by disproportionation.13 However, 5a is formed in only
trace amounts in the presence of this high flux of t-Bu• and the
oxidizing agent S2O82-. It is difficult to convert the adduct
radical, probably formed reversibly, to 5a in the absence of a
basic reagent. Reaction of t-BuHgCl with p-chlorobenzaldehyde
failed to yield alkylation products. If para attack by t-Bu• had
occurred the resulting cyclohexadienyl radical would have
readily eliminated Cl• with the formation of 5a. There was also
no indication of any product formation from benzaldehyde or
p-chlorobenzaldehyde involving t-Bu• addition to the carbonyl
group or abstraction of the aldehyde hydrogen atom. Photo-
chemical reactions of t-BuHgI/DABCO with benzophenone,
acetophenone, or tert-butyl phenyl ketone also yielded only the
para substitution products: 5b (50% yield in 35 h accompanied
by 13% of 4,4′-di-tert-butylbenzophenone), 5c (32% in 44 h),
5d (19% in 47 h). Again, only traces of 5 are formed in the
absence of DABCO. Ethyl benzoate was much less reactive
than benzaldehyde and gave only 10% of ethyl 4-tert-butyl-
benzoate in 42 h, while benzonitrile gave 24% of the 4-tert-
butyl derivative in 28 h. With PhNO2 essentially no reaction
was observed.14
Table 1. Photolysis of t-BuHgX with Benzaldehyde in Me2SO at
35-40 °Ca
X
additive (equiv)
time, h
% 5ab
Cl
I
I
Cl
I
I
none
none
KI (4), K2S2O8 (2)
DABCO (4)
DABCO (4)
DABCO (4)
24
24
24
24
24
42
3
0
4
42
48
60
Phthalimides. Phthalimides are surprisingly reactive upon
photolysis with t-BuHgX in Me2SO (Table 2). Photolysis of
6a with t-BuHgCl or t-BuHgI produces only traces of 7a in the
absence of DABCO but excellent yields in its presence. Dark
reactions of t-BuHgI in the presence of KI and DABCO also
produce 7a.15 The formation of 7c occurred in the absence of
DABCO upon photolysis with t-BuHgCl/KI or in the dark with
t-BuHgCl/KI/K2S2O8. The yield of 7c upon photolysis with
t-BuHgCl/KI was drastically reduced by the presence of PTSA
suggesting the intermediacy of 8, even in the absence of
DABCO. Although 6c reacted to yield the aromatic substitution
a 0.5 M PhCHO and 2 M t-BuHgX irradiated with a 275 W
fluorescent sunlamp. b By GC with toluene as an internal standard.
Unreacted benzaldehyde remained in all experiments.
Results and Discussion
1,4-Naphthoquinone. Photolysis with t-BuHgCl in benzene
at 35-40 °C produces the reductive and oxidative alkylation
products 3a and 4a.4 In the presence of acids such as HOAc
or NH4+, 3a is the exclusive product, but in the presence of
DABCO only 4a is formed.4 The results are consistent with
Scheme 3.
product 7c, 6d reacted with t-Bu• to form t-BuSPh and the
N-phthalimidyl radical which was converted to 6a and alkylated
to 7a.
With i-PrHgCl, photolysis in Me2SO produces only the mono-
+
(4b) and diisopropylated quinones even in the presence of NH4
or I-. Apparently conversion of the adduct radical to the radical
ion followed by electron transfer to RHgX occurs readily in
Me2SO. However, in benzene in the absence of any additive,
3b and 4b are formed (44 and 38%, respectively), while in the
presence of 4 mol % of HOAc the yield of 3b increases to 46%
and 4b decreases to 14%, and with 2 equiv of NH4+, 3b and
4b are formed in 58 and 24% yield. In the presence of 4 equiv
of DABCO only 4b is observed in 77% yield.
Benzothiazole and Benzimidazole.8 The thiazole and imi-
dazole undergo facile attack of t-Bu• at C-2. In the presence
+
of PTSA or NH4 the thiazole yields only the reductive
alkylation product, while in the presence of DABCO only the
oxidative alkylation product is formed. The reactions of
benzothiazole thus parallel those of 1,4-naphthoquinone, see
Scheme 3. 5-Methylbenzimidazole gives only the oxidative
alkylation product possibly by the imidazole serving as the base
in Scheme 2. The yield of alkylation product is drastically
reduced by excess PTSA but without the formation of the
reductive alkylation product.
Benzaldehyde and Phenones. Photolysis of t-BuHgX (X
) Cl, I) with PhCHO in Me2SO in the presence of DABCO
forms 4-tert-butylbenzaldehyde (5a) slowly but cleanly. In the
absence of DABCO essentially no reaction is observed, Table
1.
(13) Russell, G. A.; Guo, D.; Baik, W.; Herron, W. J. Heterocycles 1989,
28, 143.
(14) With PhNO2 and t-BuHgX in Me2SO in the presence of I- good
yields of PhN(t-Bu)OBu-t are observed in the presence or absence of
DABCO: Russell, G. A.; Yao, C.-F. Heteroatom Chem. 1993, 4, 433. Under
forcing conditions (5 equiv of t-BuHgI, 10 equiv of KI, DMF, hν for 10 h)
65% of PhN(t-Bu)OBu-t and 30% of p-t-BuC6H4N(t-Bu)OBu-t are observed.
(15) The thermal or photochemical formation of t-Bu• from t-BuHgI is
greatly increased by the presence of I-, possibly from comproportionation
to form (t-Bu)2Hg: Russell, G. A.; Hu, S.; Herron, S.; Baik, W.;
Ngoviwatchai, P.; Jiang, W.; Nebgen, M.; Wu, Y.-W. J. Phys. Org. Chem.
1988, 1, 299.
With KI and K2S2O8 as additives, t-Bu• formation is very
rapid as evidenced by CIDNP for the Me2CdCH2 and Me3CH

Base-Promoted Aromatic Alkylations by Alkylmercury Halides
J. Am. Chem. Soc., Vol. 119, No. 38, 1997 8797
Table 2. tert-Butylation of Phthalimides by t-BuHgX in Me2SO at
35-40 °Ca
and di-tert-butylation products 11a and 12a, reaction 1. The
initial kinetic chain length measured by the (t-Bu)2NO• inhibition
substrate
X
additive (equiv)
time, h product (%)
6a
6a
6a
6a
6a
6a
6b
6b
6c
6c
6c
6c
Cl, I
Cl
Cl
none
DABCO (4)
DABCO (4)
20
10
20
20
5
35
20
20
14
14
14
14
7a (trace)b
7a (59)b
7a (93)b
7a (91)b
7a (63)b
7a (60)b,c
7b (30)d
7b (65)d
7c (5)d
Cl (2 equiv) DABCO (4)
I (2 equiv)
I
Cl
Cl
Cl
Cl
Cl
Cl
DABCO (4)
DABCO (4), KI (4)
KI (4)
DABCO (4)
none
KI (4)
K2S2O8 (2), KI (4)
PTSA (4), KI (4)
7c (48)d
7c (76)d,e
7c (11)d
method17 was 22 for 0.05 M 1,3-dicyanobenzene upon sunlamp
photolysis with 4 equiv each of t-BuHgCl and DABCO at 35-
40 °C. The alkylation also occurred slowly in the dark by use
of t-BuHgI/KI.15 This dark reaction occurred even in the
absence of DABCO although it was greatly accelerated by its
presence (Table 3). From the inhibition period observed with
2 mol % of (t-Bu)2NO• (30 h) an initial kinetic chain length of
1000 was calculated for the iodide ion promoted dark reaction.
Isophthaldehyde was less reactive than 1,3-dicyanobenzene
presumably because of steric strain in forming 10 with Z1 )
CHO. Photolysis with 2 equiv of t-BuHgCl and 4 equiv of
DABCO for 4 h produced 46% of 11b and 12% of 12b. The
3-cyano derivatives of ethyl benzoate or benzaldehyde were
more reactive. Thus, photolysis with 4 equiv each of t-BuHgCl
and DABCO for 12 h produced 11c in 99% yield without the
formation of di-tert-butylated product. With 3-cyanobenzal-
dehyde, 3 h of photolysis yielded 11d in 84% yield accompanied
by 12% of 12d. No reaction was observed with m-cyanoanisole
or m-cyanonitrobenzene which appeared to act as a radical chain
inhibitor.
a Photolysis of 0.5 M substrate by a 275 W fluorescent sunlamp
with 4 equiv of t-BuHgX. b Yield in Me2SO-d6 by 1H NMR with toluene
as an internal standard. c Dark reaction. d GC yield with toluene as an
internal standard after workup with aqueous Na2S2O8. e In a dark
reaction 7c was formed in 51% yield.
Table 3. tert-Butylation of 1,3-Dicyanobenzene in Me2SO
t-BuHgX DABCO, KI
(X, equiv)
(equiv)
conditions
11aa (%) 12aa (%)
Cl, 1
Cl, 1
Cl, 4
I, 2
I, 4
I, 4
4, 0
4, 0
4, 0
4, 2
4, 4
0, 4
hν, 20 min, 35 °C
hν, 1.5 h, 35 °C
hν, 4.5 h, 35 °C
dark, 5.5 h, 25 °C
dark, 19 h, 25 °C
dark, 19 h, 25 °C
26
44
1
27
99
66
99
3
31
20
a By H NMR with toluene as an internal standard in Me2SO-d6.
1
Other Ortho Disubstituted Benzenes. In sharp contrast to
the phthalimides, the disubstituted benzene derivatives phthalic
anhydride, phthaldehyde, or dimethyl phthalate failed to undergo
reactions with t-BuHgCl/DABCO/hν. For the aldehyde and
ester steric inhibition of resonance in the adduct radical 9 appears
to be involved. Phthalic anhydride has a more negative
With a radical having a lower steric requirement than t-Bu•,
isophthalate esters are also reactive. Thus, photolysis of diethyl
isophthalate for 11 h with 2 equiv of i-PrHgCl and 4 equiv of
DABCO formed 11e (67%) and 12e (12%). Under the same
conditions BuHgCl gave in 20 h 18% of 11f.
1,4-Disubstituted Benzenes. The 1,4-disubstituted benzenes
were much less reactive than the 1,3-derivatives. No reaction
was observed for dimethyl terephthalate or terephthaldehyde.
However, 1,4-dicyanobenzene formed a mixture of 13a and 14
in 58 and 11% yields upon photolysis for 3 h which increased
to 61% and 30% after 10 h. Ethyl p-cyanobenzoate reacted
more slowly but cleanly formed 13b in yields of 24, 46, 60,
and 80% upon photolysis for 6, 18, 28, and 80 h, respectively.
reduction potential than phthalimide (-1.16 vs -0.70 V, SCE,
in H2O)16 which may explain the reactivities observed since
the transition state for attack of the nucleophilic t-Bu• upon an
aromatic ring should be stabilized by t-Bu+ ArX•-. 1,2-
Dicyanobenzene was examined because of the low steric
requirements of the cyano group as well as its favorable
reduction potential. Indeed, sunlamp photolysis of the dinitrile
with 4 equiv each of t-BuHgCl and DABCO in Me2SO for 3 h
produced 90% of 4-tert-butyl-1,2-dicyanobenzene and 10% of
1,5-di-tert-butyl-2,3-dicyanobenzene, while after 10 h of pho-
tolysis the yields were 84 and 16%, respectively.
Effect of DABCO on Intramolecular Cyclizations To
Form r-Tetralones. Photolysis of t-BuHgX and PhCOCH2-
CHdCH2 leads to isomerization to give the R,â-unsaturated
ketone. In the presence of I- good yields of the adduct
PhCOCH(HgI)CH(CH3)CMe3 are formed as evidenced by the
isolation of PhCOCH2CH(CH3)CMe3 after aqueous workup.17
With 1-phenyl-4-penten-1-one (15a) modest yields of the
R-tetralone 16a are observed with a significant increase in yield
in the presence of DABCO. The reaction seems to fit Scheme
2 where loss of a proton from the cyclized cyclohexadienyl
1,3-Disubstituted Benzenes. For 1,3-disubstituted benzenes
the adduct radicals 10 can be stabilized by both substituents.
With t-Bu• the adduct radicals are readily formed only when
Z1 has a low steric requirement such as cyano or formyl. Thus,
although no reaction was observed for diethyl isophthalate, 1,3-
dicyanobenzene readily underwent base-promoted tert-butyla-
tion. Table 3 summarizes results for the formation of the mono-
(16) Schwabe, K. Polarographic and Chemische Konstitution Organische
Verbindungen; Academie-Verlag: Berlin, 1957.
(17) Russell, G. A.; Li, C.; Chen, P. J. Am. Chem. Soc. 1995, 117, 3645;
1996, 118, 9831.

8798 J. Am. Chem. Soc., Vol. 119, No. 38, 1997
Russell et al.
Table 4. Photolysis of RHgCl with 1-Phenyl-4-penten-1-one To
Form 16aa
transfer from the acyl radical to t-BuHgCl followed by trapping
R
X
additive (equiv)
time, h
% 16a
t-Bu
t-Bu
t-Bu
i-Pr
I
none
24
24
24
24
24
8
8
42
9
Cl
Cl
I
K2S2O8 (2)
DABCO (4)
none
i-Pr
Cl
DABCO (4)
37
of the acyl cation by Me2SO and hydrolysis, reaction 3. When
Et2NH was used as the base in PhH solution, photolysis of 15c
with t-BuHgCl yielded a mixture of 16c and the N,N-diethy-
lamide expected from the rearranged acyl cation. Rearranged
cyclized product (such as 17),19 or decarbonylated products were
a Sunlamp irradiation of 0.02 M substrate with 0.08 M t-BuHgX in
Me2SO at 35-40 °C. b GC yield with toluene as an internal standard
after workup with aqueous Na2S2O3.
Scheme 4
RCO• + t-BuHgCl f RCO+ + t-Bu• + Hg0 + Cl- (3)
not detected indicating that the oxidation of the acyl radical
must occur quite readily in either Me2SO or PhH solution. In a
similar manner, it has been previously observed that iminyl
radicals (e.g., t-BuCdNR•) are oxidized by t-BuHgX in Me2-
SO to form the amides or in benzene in the presence of aniline
to form the amidines (t-BuC(NHPh)dNR).20,21 The yields are
excellent with R ) Ph, and the amides and amidines can even
be detected even with R ) t-Bu or PhCH2 where â-elimination
from the imidyl radical occurs readily.21
Attempted cyclizations of allyl benzoate or diallyl isophthalate
failed completely with t-BuHgCl/DABCO/hν. The reactions
formed t-BuCH2CHdCH2 by â-elimination reaction 4. Numer-
ous other allyl alcohol derivatives have been observed to yield
radical yields a radical anion which readily transfers an electron
to t-BuHgX. Table 4 summarizes the observed yields of 16a.
elimination products upon photolysis with t-BuHgX, and in
some cases the intermediate adduct organomercury halides have
been detected, e.g., t-BuCH2CH(HgCl)CH2Y with Y ) OH,
OAc, OPh.22 Similar addition-eliminations occur with deriva-
tives of propargyl alcohol including the benzoate ester.22 In
the present case cyclization is slow because of the preferred
s-trans conformation of the ester radical and formation of the
1:1 adduct by reaction with t-BuHgCl is the preferred reaction
course.17
Spirocyclization,18,19 as shown in Scheme 4, would not be
revealed in the reactions of 15a (Z1 ) Z2 ) H) if the rearranged
radical underwent cyclization. It was also not detected with
Z1 ) H and Z2 ) CH3CO since 15b upon sunlamp photolysis
in Me2SO for 18 h with t-BuHgCl (3 equiv) and DABCO (4
equiv) formed a mixture of 16b (R ) t-Bu, 31%) and a second
isomer assigned structure 18 (32%).
Reactivity of Substrates toward t-Bu• in Competitive
Oxidative Alkylations. Substrates should demonstrate a con-
stant relative reactivity in oxidative and reductive alkylations
(e.g., Scheme 3) provided that radical additions to the substrates
are irreversible. This has been shown to be the case in
competitive reductive (with I- added) and oxidative (in the
presence of DABCO) alkylations of N-methylmaleimide and
fumaronitrile where the nitrile is 2.2-2.5 times as reactive as
the imide under all conditions.7 An extensive list of relative
reactivities of substrates toward t-Bu• in reductive alkylations
has been reported using reaction 5 as a standard.23 In Table 5
similar relative reactivities for oxidative alkylations are sum-
1
The formation of 18 was unexpected, but the H NMR of
the aromatic hydrogens requires a 1,3-diacyl substitution for
16b (δ for the aromatic hydrogen between the two acyl groups
∼8.5) and a vicinally trisubstituted benzene for 18. Only the
two isomers 16b and 18 were detected in the crude reaction
1
mixture as judged from H NMR for tert-butyl groups.
With 15c (Z1 ) CO2Et, Z2 ) H) evidence for spirocyclization
was obtained, but in a rather unexpected manner. Reaction
according to the recipe used for 15b, yielded only two tert-
butylated products. Isolation and characterization showed the
products to be 16c (R ) t-Bu, 40%) and the rearranged
carboxylic acid 19 (33%). This product requires the rearrange-
ment of the initial adduct radical, undoubtedly facilitated by
the para carbonyl substituent, followed by oxidation of the acyl
radical, reaction 2. The oxidation probably involves electron
k ) 2.5 × 104
M-1 s
t-Bu• + (E)-ICHdCHPh
-18
35 °C
(E)-t-BuCHdCHPh + I• (5)
marized based on product analysis of competitive tert-butyla-
tions.
(20) Russell, G. A. NATO ASI Series C 1989, 257, 13.
(21) Russell, G. A.; Rajaratnam, R.; Chen, P. Acta Chem. Scand., in
press.
(18) Winstein, S.; Heck, R.; Lapporte, S.; Baird, R. Experientia 1956,
12, 138.
(22) Russell, G. A.; Ngoviwatchai, P.; Wu, Y. W. J. Am. Chem. Soc.
1989, 111, 4921.
(19) Urry, W. H.; Trecker, D. J.; Hartzler, H. D. J. Org. Chem. 1964,
29, 1663.
(23) Russell, G. A.; Shi, B. Z.; Jiang, W.; Hu, S.; Kim, B. H.; Baik, W.
J. Am. Chem. Soc. 1995, 117, 3952.

Base-Promoted Aromatic Alkylations by Alkylmercury Halides
J. Am. Chem. Soc., Vol. 119, No. 38, 1997 8799
Table 5. Reactivity of t-Bu• with Substrates Giving Substitutive
(Oxidative) Alkylation at 35 °C in Me2SO
reaction of the dicyanobenzene radical anions with t-BuI does
not generate a free tert-butyl radical that can continue a chain
reaction. The formation of I• from reactions involving t-BuI
may also be a complicating fact since I• would terminate an
electron transfer chain reaction of t-BuI. For t-BuHgI chain
reactions, I• does not terminate the reaction since reaction 6
occurs readily.27 In fact, chain processes such as reaction 5
involve I• as a chain propagating species.28
substrate
PhCHO
standard
reactivitya
(E)-PhCHdCHI
(E)-PhCHdCHI
(E)-PhCHdCHI
(E)-PhCHdCHI
(E)-PhCHdCHI
(E)-PhCHdCHI
(E)-PhCHdCHI
ethyl fumarate
0.015b
0.047b
0.12b
PhCOCH2CH2CHdCH2
phthalimide
2,6-Me2PyH+
1,3-dicyanobenzene
PhNC
0.86c
1.9b
6.5d
PyH+
15c
I• + t-BuHgX f t-Bu• + IHgX
Experimental Section
(6)
N-methylmaleimide
fumaronitrile
fumaronitrile
2700b,e,f
6400b,e
6000b,f
ethyl fumarate
N-methylmaleimide
a Relative to (E)-PhCHdCHI. b In the presence of 1-4 equiv of
DABCO. c Reference 11b. d To yield PhNtCCMe3+ which is converted
to PhNHCOCMe3 in Me2SO. e In reductive alkylation ethyl fumarate
is 460 times as reactive as (E)-PhCHdCHI. In the presence of DABCO,
ethyl fumarate gives only the reductive alkylation product while
N-methylmaleimide or fumaronitrile give only oxidative alkylation.f In
reductive alkylation (presence of I-) N-methylmaleimide is 2300-2800
times as reactive as (E)-PhCHdCHI and fumaronitrile is 2.5 times as
reactive as N-methylmaleimide.
General Procedures. The aromatic substrates (1-2 mmol) and
reagents were dissolved in 4 mL of Me2SO in a Pyrex test tube under
a nitrogen atmosphere, often with continuous nitrogen bubbling, and
irradiated with a 275 W Sylvania fluorescent sunlamp approximately
25 cm from the reaction tube. Workup involved treatment with 50
mL of aqueous Na2S2O3 followed by CH2Cl2 extraction and washing
of the CH2Cl2 extract with brine. After drying (MgSO4) and evaporation
of the solvent the reaction products were isolated on TLC plates using
hexane-ethyl acetate as the eluent.
For reactions monitored by 1H NMR integration, the substrate (0.05
mmol) and added reagents were dissolved in 0.6 mL of Me2SO-d6 in
a 5 mm NMR tube with 0.1 mmol of toluene added as an internal
standard.
The present results suggest that base-promoted homolytic
aromatic substitutions may be a rather general process for
electronegatively-substituted aromatics. By judicious use of
basic reagents it may well be possible to promote other reactions
such as the classical phenylation of aromatics by benzoyl
peroxide.
1H and 13C NMR spectra were obtained in CDCl3 at 300 and 75.4
MHz with δ measured relative to internal Me4Si or the central 13C peak
of CDCl3, respectively. GCMS were obtained with a Finnegan 4000
spectrometer and HRMS with a Kratos MS-50 spectrometer. Analytical
data were obtained with a Perkin Elmer Series II Analyzer 2400 or
from Galbraith Laboratories. Melting points were determined on a
Thomas-Hoover apparatus and are uncorrected.
Attempted Aromatic Alkylations with tert-Butyl Halides.
The base-promoted tert-butylation reactions described in the
previous sections, fail completely when t-BuBr or t-BuI are
substituted for t-BuHgX. No reaction is observed in Me2SO,
DMF, or PhH upon photolysis of t-BuX and the dicyanoben-
zenes in the presence of Dabco, with AIBN at 70 °C in DMF
or PhH, or upon photolysis of Bz2O2 in DMF or PhH at 35 °C.
A chain reaction does not occur and unreacted t-BuX can be
recovered in DMF or PhH. We find these observations to be
perplexing because estimated E°-values for t-BuX reductions
suggest that these molecules should participate in electron
transfer with the dicyanobenzene radical anions. Some esti-
mated E°-values (NHE) in Me2SO and DMF are t-BuBr, -0.73,
-0.92; t-BuI, -0.56, -0.77 V.24a Although the observed
irreversible electrode reduction potentials are much more
negative than the estimated values,24 they are in the range of
those reported for t-BuHgX, e.g., t-BuHgBr, E1/2(CH3CN) )
-1.08 V (SCE);25 t-BuI, E1/2 (DMF) ) -1.84 V (SCE),24b
whereas the reduction potentials of the dicyanobenzenes are in
the range of -1.5 to -1.6 V (E°, SCE). The lack of reactivity
of t-BuBr in these reactions may reflect the slow rate of electron
transfer from the radical anion to the alkyl halide. Thus, Lund
has reported in DMF a correlation between the rate constant of
electron transfer to t-BuBr from aromatic radical anions and
the reduction potentials of the aromatics with the value for k
being only 10 L/mol s at 25 °C for an aromatic with E° ) -1.5
V (SCE).26 A rate constant of only 10 L/mol s would be too
slow for an efficient chain reaction and would lead to steady
state radical anion concentrations where bimolecular termination
reactions (k > 106 L/mol s) would become dominant. However,
Save´ant has reported in DMF that ∆Gq is 9.7 kcal/mol [k(25
°C) ) 4 × 105 L/mol s] for the reaction of t-BuI with
terephthalonitrile radical anion (E° ) -1.51 V), presumably a
dissociative electron transfer process.24b Apparently the facile
Dimethyl sulfoxide was distilled from CaH2 and stored over 4A
Molecular Sieves under nitrogen. tert-Butylmercury chloride was
prepared from HgCl2 and t-BuLi by a modification of a literature
method:29 mp 110-113 °C, 1H NMR δ 1.51. tert-Butylmercury iodide
was prepared by anion exchange with the chloride by treatment with 2
equiv of KI in Me2SO followed by hydrolysis and ether extraction.
The initially white crystals of t-BuHgI turned pale yellow when exposed
to air and light. Material with 1H NMR δ 1.53 was stored in a freezer
in the dark.
For the known 4a,30 4b,30 5a,31 5b,32 5c,33 5d34 4-(1,1-dimethylethyl)-
benzonitrile,35 4,4′-bis(1,1-dimethylethyl)benzophenone,35,36 7a,37 4-(1,1-
dimethylethyl)phthalonitrile,38 3,5-bis(1,1-dimethylethyl)phthalonitrile,38
1
12a,39 and 14,39 the observed mp and H and 13C NMR spectra were
consistent with literature values, and the compounds all gave a HRMS
consistent with their structures.
(27) Reactions of 1,3-dicyanobenzene with t-BuI in the presence of Dabco
in PhH also fails when initiation is attempted with 10% of Bu3SnSnBu3/hν
at 60 °C although under this condition t-BuI can be added to alkynes:
Curran, D. P.; Kim, D. Tetrahedron 1991, 47, 6171. Presumably Bu3-
SnSnBu3 would readily trap I•.
(28) Russell, G. A. Acc. Chem. Res. 1989, 22, 1.
(29) Kharasch, M. S.; Swartz, S. J. Org. Chem. 1938, 3, 405.
(30) Pluim, H.; Wynberg, H. J. Org. Chem. 1980, 45, 2498. Doetz, K.
H.; Muehlemeier, J.; Schubert, U.; Orama, O. J. Organomet. Chem. 1983,
247, 187. Baxter, I.; Cameron, D. W.; Sanders, J. K. M.; Titman, P. B. J.
Chem. Soc., Perkin Trans. 1 1972, 2046.
(31) Torii, S.; Takama, H.; Inokuchi, T.; Nakane, S.; Akada, M.; Saito,
N.; Sirakawa, T. J. Org. Chem. 1982, 47, 1647.
(32) Stasko, A.; Malik, L.; Mat’asova, E.; Tkac, A. Org. Magn. Res.
1981, 17, 74.
(33) Bloxsidge, J.; Jones, J. R.; Marks, R. E. Org. Magn. Res. 1970, 2,
337.
(34) Farcasiu, D.; Schlosberg, R. H. J. Org. Chem. 1982, 47, 151.
(35) Fox, M. A.; Shultz, D. J. Org. Chem. 1988, 53, 4386. Berger, S.
Tetrahedron 1976, 32, 2451.
(36) Uchiyama, M.; Suzuki, T.; Yamazaki, Y. Chem. Lett. 1983, 1201.
Cristol, S. J.; Hayes, R. A.; Haller, H. L. J. Am. Chem. Soc. 1946, 68, 913.
(37) Mikhalenko, S. A.; Barkanova, S. V.; Lebedev, O. L. J. Gen. Chem.
USSR 1971, 41, 2770.
(38) Mikhalenko, S. A.; Gladyr, S. A.; Luk’yanets, E. A. Zh. Org. Khim.
1972, 8, 341.
(39) Mella, M.; Fasini, E.; Albini, A. J. Org. Chem. 1992, 57, 3051.
(24) (a) Eberson, L. Acta. Chem. Scand. 1982, B36, 533. (b) Save´ant,
J.-M. J. Am. Chem. Soc. 1987, 109, 6788.
(25) Butin, K. P.; Magdesieva, T. V.; Rakhimov, R. D.; Reutov, O. A.
Zh. Org. Khim. 1987, 23, 2481.
(26) Lund, H.; Daasbierg, K.; Lund, T.; Pedersen, S. U. Acc. Chem. Res.
1995, 28, 313.

8800 J. Am. Chem. Soc., Vol. 119, No. 38, 1997
Russell et al.
2-(1,1-Dimethylethyl)-2,3-dihydro-1,4-naphthoquinone (3a). The
compound was isolated by flash chromatography (silica gel) with
hexane (95%)-ethyl acetate (5%) was a brown oil: FTIR (neat) 3072
(84), 217 (100), 203 (30), 115 (15). Anal. Calcd for C15H20O4: C,
68.16; H, 7.63. Found: C, 67.83; H, 7.77.
4,6-Bis(1,1-dimethylethyl)isophthaldehyde (12b). The compound
was isolated as a solid, mp 130-132 °C: 1H NMR δ 10.74 (s, 2H),
8.45 (s, 1H), 7.63 (s, 1H), 1.54 (s, 18H); 13C NMR δ 191.5, 156.6,
134.4, 133.6, 125.2, 36.7, 32.4; GC and HRMS m/z (rel intensity)
246.1604 (3, calcd for C16H22O2 246.1620), 245 (8) 231 (100), 213
(16), 115 (12), 57 (20). Anal. Calcd for C16H22O2: C, 78.01; H, 9.00.
Found: C, 78.34; H, 9.07.
5-Cyano-2,4-bis(1,1-dimethylethyl)benzaldehyde (12d). The com-
poound was isolated as a solid, mp 119-122 °C: 1H NMR δ 10.75 (s,
1H), 8.22 (s, 1H), 7.62 (s, 1H), 1.542 (s, 9H); 13C NMR δ 196.1, 158.1,
156.3, 137.5, 133.4, 124.8, 119.2, 109.2, 36.7, 36.4, 32.6, 29.9; GC
and HRMS m/z (rel intensity) 243.1623 (11, calcd for C16H21NO
243.1623), 228 (100), 210 (12), 186 (9), 154 (5), 57 (21). Anal. Calcd
for C16H21NO: C, 78.97; H, 8.70; N, 5.76. Found: C, 78.46; H, 9.09;
N, 5.56.
Diethyl 4,6-Bis(1-methylethyl)isophthalate (12e). The compound
was isolated as a liquid: 1H NMR δ 8.16 (s, 1H), 7.44 (s, 1H), 43.7
(q, J ) 7.2 Hz, 4H), 3.80 (heptet, J ) 6.9 Hz, 2H), 1.39 (t, J ) 7.2
Hz, 6H), 1.27 (d, J ) 7.2 Hz, 12H); 13C NMR δ 167.5, 153.2, 131.7,
127.4, 124.1, 60.9, 29.7, 23.7, 14.2; GC and HRMS m/z (rel intensity)
306.1827 (52, calcd for C18H26O4 306.1831), 277 (21), 261 (76), 260
(100), 259 (67), 245 (20). Anal. Calcd for C18H26O4: C, 70.56; H,
8.55. Found: C, 69.94; H, 8.71.
1
(w), 2968 (m), 2910 (w), 1695 (vs), 1595 (m), 1291 (m) cm-1; H
NMR (CDCl3) δ 8.05-7.99 (m, 2H), 7.77-7.68 (m, 2H), 3.13 (d, J )
1
5.7 Hz, 2H), 2.89 (t, J ) 5.7 Hz, 1H), 0.99 (s, 9H); H NMR (Me2-
SO-d6) δ 7.95-7.89 (m, 2H), 7.89-7.80 (m, 2H), 3.27 (dd, J ) 16.8,
6.3 Hz, 1H), 3.05 (dd, J ) 16.8, 5.7 Hz, 1H), 2.95 (t, J ) 6.0 Hz, 1H),
0.92 (s, 9H); GC and HRMS m/z (rel intensity) 216 (0.02), 201.0912
(2, calcd for C13H13O2 (M+ - Me) 201.0916), 183 (2), 160 (100), 132
(12), 104 (8), 57 (26); CIMS (NH3) 217.1230 (100, calcd for C14H17O2
(M+H+) 217.1229).
2-(1-Methylethyl)-2,3-dihydro-1,4-naphthoquinone (3b). The com-
pound was isolated as a brown oil: FTIR (neat) 3070 (w), 2966 (m),
1
2910 (w), 1693 (vs), 1595 (m) cm-1; H NMR δ 8.07-7.95 (m, 2H),
7.75-7.68 (m, 2H), 3.13-2.95 (m, 2H), 2.90-2.83 (m, 1H), 2.28 (octet,
J ) 6.6 Hz, 1H), 0.98 (dd, J ) 6.6, 1.2 Hz, 6H); GC and HRMS m/z
(rel intensity) 202.0990 (5, calcd for C13H14O2 202.0994); 187 (16),
160 (100), 1313 (23), 104 (30), 76 (31).
4-(1,1-Dimethylethyl)isophthalonitrile (11a). The compound was
isolated as a white solid, mp 56-57 °C: 1H NMR δ 7.95 (d, J ) 1.8
Hz, 1h), 7.80 (dd, J ) 8.4, 1.8 Hz, 1H), 7.65 (d, J ) 8.4 Hz, 1H), 1.55
(s, 9H); 13C NMR δ 158.8, 138.5, 135.7, 127.6, 118.0, 116.7, 112.5,
111.0, 36.3, 29.8; HRMS m/z (rel intensity) 184.1005 (calcd for
C12H12N2 184.1001). Anal. Calcd for C12H12N2: C, 78.23; H, 6.57;
N, 15.20. Found: C, 78.19; H, 6.78; N, 15.18.
1,4-Dicyano-2-(1,1-dimethylethyl)benzene (13a). The compound
was isolated as a solid, mp 150-151 °C: 1H NMR δ 7.81-7.78 (m,
2H), 7.60 (dd, J ) 7.8, 1.5 Hz, 1H), 1.55 (s, 9H); 13C NMR δ 155.1,
136.0, 130.2, 129.5, 118.5, 117.5, 116.3, 115.1, 35.9, 29.8; GC and
HRMS m/z (rel intensity) 184.1001 (17, calcd for C12H12N2 184.1001),
169 (100), 141 (30), 114 (8), 57 (5). Anal. Calcd for C12H12N2: C,
78.23; H, 6.57; N, 15.20. Found: C, 78.29; H, 6.55; N, 14.94.
Ethyl 4-Cyano-3-(1,1-dimethylethyl)benzoate (13b). The com-
pound was isolated as a liquid: 1H NMR δ 8.16 (d, J ) 1.5 Hz, 1H),
7.94 (dd, J ) 7.8, 1.5 Hz, 1H), 7.75 (d, J ) 8.1 Hz, 1H), 4.42 (q, J )
7.2 Hz, 2H), 1.56 (s, 9H), 1.42 (t, J ) 7.2 Hz, 3H); 13C NMR δ 165.4,
154.1, 135.5, 133.8, 127.3, 126.9, 119.5, 114.6, 61.6, 35.7, 30.0, 14.2;
GC and HRMS m/z (rel intensity) 231.1260 (14, calcd for C14H17NO2
231.1259), 216 (100), 188 (30), 144 (9). Anal. Calcd for C14H17NO2:
C, 72.70; H, 7.41; N, 6.06. Found: C, 72.64; H, 7.40; N, 5.93.
4-(2,2-Dimethylpropyl)-3,4-dihydro-1(2H)-naphthalenone (16a, R
) Me3C). The compound was isolated as a liquid: FTIR (CDCl3)
4-(1,1-Dimethylethyl)-N-methylphthalimide (7b). The compound
was isolated as a solid, mp 87-88 °C: 1H NMR 7.88 (d, J ) 1.2 Hz,
1H), 7.76 (d, J ) 7.5 Hz, 1H), 7.71 (dd, J ) 8.1, 1.5 Hz, 1H), 3.17 (s,
3H), 1.38 (s, 9H); GC and HRMS m/z (rel intensity) 217.1103 (25,
calcd for C13H15NO2 217.1103), 203 (12), 202 (100), 174 (37), 117
(7), 115 (13), 77 (3), 57 (3).
4-(1,1-Dimethylethyl)-N-(phenylthiomethyl)phthalimide (7c). The
compound was isolated as a liquid: FTIR (CDCl3) 1774 (s), 1722 (s),
1
1620 (m) cm-1; H NMR δ 7.86-7.85 (m, 1H), 7.75-7.70 (m, 2H),
7.50 (dd, J ) 7.5, 2.1 Hz, 2H), 7.29-7.26 (m, 3H), 5.04 (s, 2H), 1.36
(s, 9H); GC and HRMS m/z (rel intensity) 325.1133 (25, calcd for
C19H19NO2S 325.1137), 216 (100), 201 (10), 186 (12), 155 (4), 109
(5), 91 (6), 57 (2).
4-(1,1-Dimethylethyl)isophthaldehyde (11b). The compound was
isolated as a white solid, mp 42-44 °C: 1H NMR δ 10.88 (s, 1H),
10.06 (s, 1H), 8.40 (d, J ) 1.8 Hz, 1H), 8.02 (dd, J ) 8.1, 1.8 Hz,
1H), 7.68 (d, J ) 8.1 Hz, 1H), 1.57 (s, 9H); 13C NMR δ 191.4, 191.0,
158.4, 136.1, 134.5, 132.49, 132.46, 127.4, 36.4, 32.7; GC and HRMS
m/z (rel intensity) 190.0994 (11, calcd for C12H14O2 190.0994), 175
(100), 157 (24), 129 (39), 91 (16), 43 (40). Anal. Calcd for
C12H14O2: C, 75.76; H, 7.42. Found: C, 75.75; H, 7.51.
Ethyl 3-Cyano-4-(1,1-dimethylethyl)benzoate (11c). The com-
pound was isolated as a liquid: 1H NMR δ 8.34 (d, J ) 2.1 Hz, 1H),
8.15 (dd, J ) 8.4, 2.1 Hz, 1H), 7.58 (d, J ) 8.4 Hz, 1H), 4.40 (q, J )
7.2 Hz, 4H), 1.55 (s, 9H), 1.41 (t, J ) 7.2 Hz, 3H); 13C NMR δ 164.6,
158.2, 136.6, 133.4, 128.8, 126.6, 119.4, 111.1, 61.5, 36.0, 29.9, 14.2;
GC and HRMS m/z (rel intensity) 231.1259 (21, calcd for C14H17NO2
231.1259), 216 (100), 188 (36), 115 (11), 43 (12). Anal. Calcd for
C14H17NO2: C,72.70; H, 7.41; N, 6.06. Found: C, 72.95; H, 7.51; N,
6.01.
3-Cyano-4-(1,1-dimethylethyl)benzaldehyde (11d). The com-
pound was isolated as a solid, mp 112-115 °C: 1H NMR δ 10.01 (s,
1H), 8.18 (d, J ) 1.8 Hz, 1H), 8.02 (dd, J ) 8.4, 1.8 Hz, 1H), 7.70 (d,
J ) 8.4 Hz, 1H), 1.57 (s, 9H); 13C NMR 189.7, 160.0, 136.7, 134.3,
133.0, 127.3, 119.0, 112.0, 36.3, 29.9; GC and HRMS m/z (rel intensity)
187.0991 (16, calcd for C12H13NO 187.0997), 172 (100), 144 (16), 57
(4). Anal. Calcd for C12H13NO: C, 76.98; H, 7.00; N, 7.48. Found:
C, 76.49; H, 7.22; N, 7.35.
1
3063 (w), 2852 (s), 2865 (m), 1686 (vs) cm-1; H NMR δ 7.99 (d, J
) 7.2 Hz, 1H), 7.48 (t, J ) 7.2 Hz, 1H), 7.30-7.24 (m, 2H), 3.12-
3.02 (m, 1H), 2.83 (ddd, J ) 17.4, 12.3, 4.8 Hz, 1H), 2.57 (dt, J )
17.4, 4.8 Hz, 1H), 2.33-2.20 (m, 1H), 2.11 (dq, J ) 18.0, 4.5 Hz,
1H), 1.75 (dt, J ) 17.4, 4.8 Hz, 1H), 1.50 (dd, J ) 14.4, 2.1 Hz, 1H),
1.04 (s, 9H); GC and HRMS m/z (rel intensity) 216.1517 (42, calcd
for C15H20O 216.1514), 160 (5), 145 (100), 131 (21), 117 (30), 103
(7), 91 (13), 57 (25).
4-(2-Methylpropyl)-3,4-dihydro-1(2H)-naphthalenone (16b, R )
Me2CH). The compound was isolated as a liquid: FTIR (neat) 2954
1
(m), 2924 (m), 2866 (w), 1684 (s) cm-1; H NMR δ 8.01 (d, J ) 7.8
Hz, 1H), 7.48 (dd, J ) 7.8, 1.2 Hz, 1H), 7.33-7.24 (m, 1H), 3.06-
2.93 (m, 1H), 2.83-2.69 (m, 1H), 2.63-2.52 (m, 1H), 2.31-2.16 (m,
1H), 2.08-1.97 (m, 1H), 1.81-1.43 (m, 3H), 1.43 (m, 6H); GC and
HRMS m/z (rel intensity) 202.1362 (29, calcd for C14H18O 202.1358),
145 (100), 131 (19), 117 (34), 104 (27), 91 (12), 77 (9).
7-Acetyl-4-(2,2-dimethylpropyl)-3,4-dihydro-1(2H)-naphthale-
none (16b, R ) Me3C). The compound was isolated as a solid, mp
39-41 °C: 1H NMR δ 8.54 (d, J ) 2.1 Hz, 1H), 8.11 (dd, J ) 8.1,
2.1 Hz, 1H), 7.38 (d, J ) 8.1 Hz, 1H), 3.12 (m, 1H), 2.86 (ddd, J )
17.7, 12.3, 5.1 Hz, 1H), 2.64 (s, 3H), 2.64 (dt, J ) 18.0, 5.1 Hz, 1H),
2.29 (tt, J ) 12.6, 4.5 Hz, 1H), 2.19-2.09 (m, 1H), 1.77 (dd, J )
14.4, 7.8 Hz, 1H), 1.48 (dd, J ) 14.4, 2.7 Hz, 1H), 1.06 (s, 9H); 13C
NMR δ 197.7, 197.3, 155.4, 135.4, 132.4, 131.6, 129.1, 127.7, 47.9,
34.8, 34.4, 31.5, 29.9, 28.0, 26.6; GC and HRMS m/z (rel intensity)
258.1622 (57, calcd for C17H22O 258.1620), 243 (58), 188 (84), 187
(100), 115 (30).
Diethyl 4-(1-Methylethyl)isophthalate (11e). The compound was
isolated as a liquid: 1H NMR δ 8.38 (d, J ) 2.1, 1H), 8.10 (dd, J )
8.4, 2.1 Hz, 1H), 7.48 (d, J ) 8.4 Hz, 1H), 4.39 (q, J ) 7.2 Hz, 2H),
4.38 (q, J ) 7.2 Hz, 3H), 3.76 (heptet, J ) 6.9 Hz, 1H), 1.41 (t, J )
7.2 Hz, 3H), 1.40 (t, J ) 7.2 Hz, 3H), 1.28 (d, J ) 6.9 Hz, 6H); 13C
NMR δ 167.6, 165.8, 154.4, 132.2, 130.8, 130.5, 127.8, 126.3, 61.1,
61.0, 29.7, 23.6, 14.2, 14.15; GC and HRMS m/z (rel intensity)
264.1361 (76, calcd for C15H20O4 264.1362), 236 (26), 219 (92), 218
4-(2,2-Dimethylethyl-6-(ethoxycarbonyl)-2,3-dihydro-1(2H)naph-
thalenone (16c, R ) Me3C). The R-tetralone was isolated as a
liquid: 1H NMR δ 8.04 (d, J ) 8.1 Hz, 1H), 7.95 (s, 1H), 7.91 (dd, J

Base-Promoted Aromatic Alkylations by Alkylmercury Halides
J. Am. Chem. Soc., Vol. 119, No. 38, 1997 8801
) 8.1, 1.8 Hz, 1H), 4.40 (q, J ) 7.2 Hz, 2H), 3.13 (m, 1H), 2.85 (ddd,
J ) 17.4, 12.4, 5.1 Hz, 1H), 262 (dt, J ) 17.7, 4.8 Hz, 1H), 2.27 (tt,
J ) 13.5, 4.5 Hz, 1H), 2.19-2.10 (m, 1H), 1.75 (dd, J ) 14.7, 8.1 Hz,
1H), 1.53 (dd, J ) 14.7, 3.0 Hz, 1H), 1.41 (t, J ) 7.2 Hz, 3H), 1.06 (s,
9H); 13C NMR δ 198.03, 165.9, 150.2, 145.1, 134.6, 129.9, 127.2,
127.0, 61.4, 48.1, 34.7, 34.5, 31.5, 29.9, 28.1, 14.1; GC and HRMS
m/z (rel intensity) 288.1721 (35, calcd for C18H24O3 288.1725), 243
(14), 232 (14), 218 (74), 217 (100).
5-Acetyl-4-(2,2-dimethylpropyl)-2,3-dihydro-1(2H)-naphthale-
none (18). The compound was isolated as a liquid: 1H NMR δ 8.15
(dd, J ) 7.8, 1.5 Hz, 1H), 7.76 (dd, J ) 7.5, 1.5 Hz, 1H), 7.37 (t, J )
7.5 Hz, 1H), 3.93 (dq, J ) 10.8, 3.0 Hz, 1H), 2.87 (ddd, J ) 18.6,
14.4, 5.7 Hz, 1H), 2.60 (ddd, J ) 18.6, 5.4, 2.1 Hz, 1H), 2.33 (m, 1H),
2.13 (tt, J ) 14.4, 4.2 Hz, 1H), 1.61 (dd, J ) 14.4, 11.4 Hz, 1H), 1.32
(dd, J ) 14.7, 2.7 Hz, 1H), 1.02 (s, 9H); 13C NMR δ 202.0, 198.3,
149.8, 137.8, 133.4, 133.2, 130.5, 126.0, 46.3, 32.9, 31.2, 30.8, 30.6,
25.0, 30.3; GC and HRMS m/z (rel intensity) 258.1620 (39, calcd for
C17H22O2 258.1620), 243 (6), 201 (100), 187 (21), 147 (14), 115 (16).
4-(4-Ethoxycarbonylphenyl)-6,6-dimethylheptanoic Acid (19).
The compound was isolated as a liquid: 1H NMR δ 10.5 (br s, 1H),
7.98-7.94 (m, 2H), 7.25-7.22 (m, 2H), 4.36 (q, J ) 7.2 Hz, 1H),
2.78-2.69 (m, 1H), 2.18-1.72 (m, 1H), 1.56 (dd, J ) 14.1, 3.3 Hz,
1H), 1.38 (q, J ) 7.2 Hz, 3H), 0.76 (s, 9H); 13C NMR δ 179.0, 166.6,
151.8, 129.8, 128.5 127.9, 60.8, 50.4, 42.0, 34.0, 31.9, 31.3, 30.0, 14.3;
GC and HMRS m/z (rel intensity) 306.1827 (48, calcd for C18H26O4
306.1831), 261 (28), 249 (65), 203 (64), 189 (92), 177 (100).
Acknowledgment. This work was supported by grants from
the National Science Foundation (CHE-9220639) and The
Petroleum Research Fund (32021-AC4).
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