Selective conversion of diallylanilines and arylimines to quinolines

Article abstract of DOI:10.1021/jo026737j

A variety of diallylanilines are shown to undergo cobalt - carbonyl catalyzed rearrangement to quinolines. Diallylanilines are also used as allyl transfer reagents to convert benzaldimines into quinolines. Substitution in the 2- and 3-positions of the quinoline is featured in all transformations.

Full text of DOI:10.1021/jo026737j

Selective Con ver sion of Dia llyla n ilin es a n d Ar ylim in es to
Qu in olin es
J osemon J acob and William D. J ones*
Department of Chemistry, University of Rochester, Rochester, New York 14627
jones@chem.rochester.edu
Received November 19, 2002
A variety of diallylanilines are shown to undergo cobalt-carbonyl catalyzed rearrangement to
quinolines. Diallylanilines are also used as allyl transfer reagents to convert benzaldimines into
quinolines. Substitution in the 2- and 3-positions of the quinoline is featured in all transformations.
In tr od u ction
been reported.15 Despite the advances in methodology
toward the construction of quinoline derivatives, the
development of catalytic routes toward their synthesis
remains an active area of research. We recently discov-
ered a cobalt-catalyzed conversion of mono- and diallyl-
anilines to quinolines.16 Arylimines have also been found
to undergo selective cross-coupling with diallylanilines
to generate quinolines, and the results of a detailed
investigation are reported here.
Transition metal catalyzed heteroannulation provides
a useful and convenient tool for the construction of
N-heterocycles.1-3 Quinolines and their derivatives form
an interesting class of compounds in that they display
attractive applications as pharmaceuticals as well as
being general synthetic building blocks due to their
chemical and biological relevance.4,5 Many transition
metal catalyzed processes have been developed for the
synthesis of quinolines. For example, several ruthenium,6
rhodium,7 palladium,8 and iron9 complexes have been
shown to catalyze the formation of 2,3-substituted quino-
lines from nitrobenzene and aldehydes or alcohols in the
presence of CO. Also, aniline was shown to undergo
N-heterocyclization to generate quinolines with aliphatic
aldehydes with use of ruthenium,10 rhodium,11 and pal-
ladium complexes.12,13 Recently, RuCl3/SnCl2 was shown
to catalyze formation of 2,3-disubstituted quinolines from
aniline and triallylamine at 180 °C.14 A new Domino
synthesis of quinolines from aniline and styrene has also
Resu lts a n d Discu ssion
Con ver sion of Dia llyla n ilin es to 2,3-Su bstitu ted
Qu in olin es. N,N-Diallylaniline (1), when heated with
10 mol % of Co2(CO)8 and 1 atm of CO at 95 °C, leads to
the selective formation of 2-ethyl-3-methylquinoline (2)
in 63% isolated yield (eq 1). Aniline and propene are also
(1) Hegedus, L. S. Angew. Chem., Int. Ed. Engl. 1988, 27, 1113.
(2) Hegedus, L. S.; Allen, G. F.; Bozell, J . J . J . Am. Chem. Soc. 1978,
100, 5800.
(3) Diamond, S. E.; Szalkiewicz, A.; Mares, F. J . Am. Chem. Soc.
1979, 101, 490.
(4) Balasubramanian, M.; Keay, J . G. In Comprehensive Heterocyclic
Chemistry II; Katritzky, A. R., Rees, C. W., Scriven, E. F. V., Eds.;
Pergamon Press: Oxford, UK, 1996; Vol. 5, p 245.
(5) J ones, G. In Comprehensive Heterocyclic Chemistry II; Katritzky,
A. R., Rees, C. W., Scriven, E. F. V., Eds.; Pergamon Press: Oxford,
UK, 1996; Vol. 5, p167.
observed as products in the reaction. The presence of CO
is necessary to stabilize Co2(CO)8 under the reaction
conditions. The reaction is easily extended to a range of
diallylanilines with varying substituents on the aromatic
ring. The results are summarized in Table 1. The 2-ethyl-
3-methyl-substitution pattern in the product is common
to all quinolines derived from diallylanilines.
Similar product selectivity and substitution pattern
have been reported in the literature for quinoline syn-
thesis from aniline and allyl alcohols or R,â-unsaturated
aldehydes catalyzed by ruthenium complexes.6,10,11 Sub-
stituents are easily introduced at the 5-, 6-, 7-, and
8-positions of the quinoline skeleton. For entry 6, almost
equimolar amounts of both regioisomers are formed in
the reaction. Reaction of a four-carbon allyl fragment as
(6) Watanabe, Y.; Tsuji, Y.; Ohsuji, Y. Tetrahedron Lett. 1981, 22,
2667.
(7) Watanabe, Y.; Suzuki, N.; Tsuji, Y.; Shim, S. C.; Mitsudo, T. Bull.
Chem. Soc. J pn. 1982, 55, 1116.
(8) Watanabe, Y.; Tsuji, Y.; Shida, J . Bull. Chem. Soc. J pn. 1984,
57, 435.
(9) Watanabe, Y.; Takatsuki, K.; Shim, S. C.; Mitsudo, T.; Takegami,
Y. Bull. Chem. Soc. J pn. 1978, 51, 3397.
(10) Watanabe, Y.; Tsuji, Y.; Ohsugi, Y.; Shida, J . Bull. Chem. Soc.
J pn. 1983, 56, 2452.
(11) Watanabe, Y.; Shim, S. C.; Mitsudo, T. Bull. Chem. Soc. J pn.
1981, 54, 3460.
(12) Larock, R. C.; Hightower, T. R.; Hasvold, L. A.; Peterson, K. P.
J . Org. Chem. 1996, 61, 3584.
(13) Larock, R. C.; Kuo, M.-Y. Tetrahedron Lett. 1991, 32, 572.
(14) Cho, S. C.; Ho Oh, B.; Shim, S. C. Tetrahedron Lett. 1999, 40,
1499.
(15) Beller, M.; Thiel, O. R.; Trauthwein, H.; Hartung, C. G. Chem.
Eur. J . 2000, 6, 2513.
(16) Proceedings from the 10th ISRHHC: J acob, J .; Cavalier, C. K.;
J ones, W. D.; Godleski, S. A.; Valente, R. R. J . Mol. Catal. A 2002,
183, 565-570.
10.1021/jo026737j CCC: $25.00 © 2003 American Chemical Society
Published on Web 04/04/2003
J . Org. Chem. 2003, 68, 3563-3568
3563

J acob and J ones
TABLE 1. Isola ted Yield s for th e Con ver sion of
Dia llyla n ilin es to Qu in olin esa
Cr oss-Cou p lin g of Ar ylim in es w it h Dia llyla n i-
lin es. Allylcobalt tricarbonyl17 and monoallylaniline are
the only intermediates observed in the reaction when
1
followed by H NMR spectroscopy. The ability of cobalt
hydrides to isomerize double bonds18 suggested that
imines are likely intermediates in the reaction. To test
this, the cross-coupling of imine 3 was studied with
diallylaniline in the presence of 10 mol % of Co2(CO)8.
As anticipated, the cross-coupled quinoline product 4 was
isolated in 47% yield (eq 2). A small amount (<5%) of
quinoline formed from diallylaniline by the reaction
reported above is also observed in the reaction. The only
other products observed are the secondary amine (formed
by reduction of the imine) and aniline (formed from
diallylaniline after transfer of its two allyl groups). This
greatly improves the scope of this cobalt-catalyzed reac-
tion in that it allows for the introduction of varying
substituents at the 2-position of the quinoline skeleton.
This unique cross-coupling reaction is easily extended
to a range of arylimines as recorded in Table 2.19 For
these experiments, 0.6-0.7 equiv of diallylaniline was
used as the allyl source. The yields reported are based
on the starting imine. The same secondary amine formed
by reduction of the imine is also observed for all sub-
strates. The reaction is quite versatile for imines derived
from aniline and various ortho- and para-substituted
aldehydes. No cross-coupling product and only 2-ethyl-
3-methylquinoline was observed for entry 6 in Table 2.
This is most likely due to the formation of a stable chelate
complex with Co2(CO)8.
Small amounts (2-4%) of a carbonylation product were
observed for entry 7 in Table 2. In the absence of
diallylaniline, the other conditions remaining the same,
this carbonylation product is the sole product in the
system although the reaction is very slow (14 days at 120
°C). This product was identified as a five-membered-ring
lactam.20 For entries 9-14 where the imine is derived
from anilines bearing a ring substituent, the aniline
formed in the reaction could undergo an imine exchange
reaction with the substrate as shown in eq 3. Although
a
10% Co2(CO)8 used in all the experiments; typical reaction
b
time is 36-48 h. Both regioisomers are formed in an ap-
proximately 1:1 ratio. c Stoichiometric reaction.
in entry 7 led to 2-propyl-3-ethyl substitution in the
quinoline product. A dicinnamylaniline as in entry 8
leads to more of the reduction products, namely aniline
and â-methylstyrene. Although a 4-methoxy substituent
is easily introduced to the quinoline skeleton, coordinat-
ing substituents at the 2-position of the diallylaniline
largely inhibit the reaction. While entry 10 gave a 15%
yield of the benzimidazole derivative in a stoichiometric
reaction, no reaction was observed with entries 11 and
12 even at 120 °C. This is most likely due to the initial
formation of a stable chelate complex with Co2(CO)8,
which is rendered unreactive.
there is no significant effect of this equilibration for
(17) Heck, R. F.; Breslow, D. S. J . Am. Chem. Soc. 1961, 83, 1097.
(18) Kumobayashi, H.; Akutagawa, S.; Otsuka, S. J . Am. Chem. Soc.
1978, 100, 3949.
(19) For a recent comprehensive account of transition metal cata-
lyzed cross-coupling reactions, see: Stang, P. J .; Diederich, F. Metal-
Catalyzed Cross-coupling Reactions; Wiley-VCH: New York, 1998.
(20) Similar reactivity of imines has been reported with transition
metal carbonyls in the literature, see: Bruce, D. W.; Liu, X.-H. J. Chem.
Soc., Chem. Commun. 1994, 729. See Experimental Section for data
on this compound, 6-(dimethylamino)-N-phenylphthalimidine.
3564 J . Org. Chem., Vol. 68, No. 9, 2003

Rearrangement of Deallylanilines to Quinolines
TABLE 2. Isola ted Yield s of Qu in olin e Der iva tives by
Cr oss-Cou p lin g w ith Dia llyla n ilin ea
TABLE 3. Isola ted Yield s of Qu in olin es by
Cr oss-Cou p lin g of Im in es w ith Dia llyla n ilin ea
a
The yields reported are based on the starting imine; 10%
catalyst loading; typical reaction time is 36-48 h.
imines derived from aniline bearing a para substutuent
(entries 9-12), it is significant for imines derived from
ortho-substituted anilines (13 and 14). For entry 13, there
is significant equilibration and the major product ob-
served is 4, which can be explained by an aniline-imine
exchange as in eq 3. For entry 14, an approximately 1:1
mixture of the two quinolines is observed.
To circumvent this problem, the cross-coupling was
studied by using diallylanilines derived from the same
aniline fragment as the imine. The results are recorded
in Table 3. This modification significantly improves the
yields of this cross-coupling reaction while avoiding any
side reactions leading from aniline-imine exchange. It
can be seen from Tables 2 and 3 that arylimines with
alkyl, alkoxy, dialkylamino, arylamino, and aryl substit-
uents on either side of the ring undergo this cross-
coupling very efficiently. Although preliminary studies
were done on an NMR scale, the reaction is easily scaled
up to 200 mg without reduction in product yield.
Mech a n istic Con sid er a tion s. While oxidative addi-
tion of a substrate to a transition metal is often a key
elementary step in many catalytic processes, the only
intermediates spectroscopically observed in this system
are allylcobalttricarbonyl and monoallylaniline. With
certain substrates, palladium and ruthenium complexes
have been shown in the past to cleave allylic C-N
bonds.21,22 While these types of bond cleavages and double
bond migrations are likely to be involved, a mechanistic
discussion at this point would have to be quite spectu-
lative without further experiments.
Although the overall reaction is the heteroannulation
of diallylaniline to give quinoline with elimination of
a
0.6-0.7 equiv of diallylaniline was used as the allyl source in
all the reactions; 10% Co2(CO)8 and 1 atm of CO is used in all the
reactions; typical reaction time is 36-48 h. NMR yield. c Small
b
(21) Moberg, C.; Antonsson, T. Organometallics 1994, 13, 1878.
(22) Hiraki, K.; Matsunaga, T.; Kawano, H. Organometallics 1994,
13, 1878.
amounts (2-4%) of a carbonylation product are also observed in
the reaction.
J . Org. Chem, Vol. 68, No. 9, 2003 3565

J acob and J ones
SCHEME 1. P r op osed Mech a n istic Sequ en ce
hydrogen, the detection and isolation of allylcobalttri-
carbonyl suggested that the reaction is not intramolecu-
lar. Also, kinetic studies showed a second order depen-
dence of initial rate on the concentration of diallylaniline,
again suggesting the possibility of allyl group transfer
between substrates. To test this, substrate 5 was synthe-
sized and its reactivity studied in the presence of
Co2(CO)8 (eq 4). Analysis of the reaction by GC-MS
carbonyl loss and addition are likely to be reversible in
many of these species. Intermediate A, formed via N-allyl
cleavage, is proposed to undergo reaction in one of two
pathways; it can either form a conjugated imine as in B
generating hydridocobaltcarbonyl or undergo orthometa-
lation to generate an intermediate of type C. Intermedi-
ate C can react with allylcobalt tricarbonyl to form
intermediate D and regenerate Co2(CO)8. HCo(CO)4 has
been shown in the literature to effect double bond
isomerizations and hence D can undergo isomerization
to generate E .18 Also, when diallylaniline was treated
with (Ph3P)3CoH synthesized independently, both allylic
double bonds were found to isomerize to the enamine
23
within minutes when followed by NMR spectroscopy.
E is poised for cyclization to generate quinoline with
elimination of H2. Alternatively, C can react with another
molecule of substrate to generate intermediates D and
A and continue the catalytic cycle. The observed cross-
coupling of imines with diallylanilines strongly suggests
the intermediacy of imines as in B, which can enter the
catalytic cycle as well. The formation of monoallylaniline
in the system can be accounted for by the reaction of A
with HCo(CO)4.
Although many other organometallic complexes were
screened for reactivity toward allylic C-N bonds, none
of them exhibited selectivity similar to Co2(CO)8. Com-
plexes tested include Ni(cod)2, (Cy3P)2Ni(CH2dCH2),
Mn2(CO)10, (Ph3P)2Ni(CO)2, Mo(CO)6, (CH3CN)3Mo(CO)3,
(CH3CN)3W(CO)3, (Ph3P)2RhCl(CO), (Ph3P)3RuClH(CO),
Rh6CO16 (cod ) cyclooctadiene, Cy ) cyclohexyl), (Ph3P)3-
RhH(CO), Ru3(CO)12, [(cod)RhCl]2, [(Ph3P)3Co(CH2CH2)]2,
[(dippe)NiH]2 (dippe ) 1,2-bis(diisopropyl-phosphino)-
ethane), and (Ph3P)3CoH(N2).
showed formation of three quinoline products: 2, 6, and
7 (the ratio from NMR of 2:6:7 is 1:4.8:5.8). If the reaction
were intramolecular, only 6 (or its isomer) is expected
as a product. This intermolecular allyl transfer was fur-
ther confirmed by reacting diallylaniline with dicinna-
myl-aniline. Detection of 6 in the reaction by NMR and
by GC-MS further supports intermolecular allyl transfer.
For the cross-coupling of imines with diallylanilines
to form quinolines, the formation of secondary amine by
reduction of the imine is an undesirable side reaction.
For every molecule of product, one molecule of hydrogen
is released in the system. Co2(CO)8 is known to form
HCo(CO)4 in the presence of H2, which could reduce the
imine. In an attempt to eliminate the reduction product,
the reaction was performed in the presence of a 10-fold
excess of tert-butylethylene. Although this eliminated the
reduction of the imine almost completely as evidenced
by GC, only a 50% conversion of the imine was observed
after 5 days. Use of a smaller mole ratio of the olefin was
less successful in eliminating the reduction reaction. In
another attempt, the reaction was done in 1,4-dioxane
but with a constant purge of CO. This was again not
successful since the allylcobalttricarbonyl formed in the
reaction is very volatile and escapes the system.
In conclusion, Co2(CO)8 is an efficient catalyst for the
conversion of diallylanilines and imines to 2-R-3-meth-
ylquinolines. The ready availability of catalyst and start-
ing reagents makes this an attractive method for the
synthesis of quinolines.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. Most manipulations were per-
formed under an N2 atmosphere, either on a high-vacuum line
with modified Schlenk techniques or in a glovebox. Tetrahy-
The proposed mechanistic sequence is outlined in
Scheme 1, although as mentioned above, the pathway is
speculative in the absence of a more thorough study. As
the reaction is conducted under an atmosphere of CO,
(23) Whitfield, J . M.; Watkins, S. F.; Tupper, G. B.; Baddley, W. H.
J . Chem. Soc., Dalton Trans. 1977, 407.
3566 J . Org. Chem., Vol. 68, No. 9, 2003

Rearrangement of Deallylanilines to Quinolines
drofuran was distilled from sodium/benzophenone ketyl solu-
tion. Co2(CO)8 was used as received. The diallylanilines used
in this study were synthesized from the corresponding aniline
by reaction with allylbromide and sodium carbonate in metha-
nol. The diallylanilines were distilled and dried over KOH prior
to use. The arylimines were synthesized by direct condensation
of the corresponding aniline and aldehyde in absolute ethanol
and recrystallized from hexanes.
29.32, 27.28, 26.57, 19.00, 12.49. MS: m/e 253, 252 (bp), 225,
210, 196, 184, 169, 115, 77. White solid.
2-Eth yl-3-m eth yl-4-p h en ylqu in olin e (en tr y 5, Ta ble 1).
1H NMR: δ 8.30 (d, 1H, J ) 8.4 Hz), 7.69 (s, 1H), 7.62 (d, 1H,
J ) 8.8 Hz), 7.50 (d, 2H, J ) 7.2 Hz), 7.33 (s, 1H), 7.22 (t, 2H,
J ) 7.2 Hz), 7.13 (t, 1H, J 6.8 Hz), 2.73 (q, 2H, J ) 7.2 Hz),
1.96 (s, 3H), 1.42 (t, 3H, J ) 7.6 Hz). 13C NMR: δ 162.86,
147.04, 141.39, 138.65, 135.50, 130.11, 129.94, 129.17, 128.34,
128.20, 127.98, 127.61, 124.89, 29.38, 18.97, 12.35. MS: m/e
247, 246 (bp), 219, 203, 189, 165, 123, 102, 77, 63. White solid.
2-Eth yl-3-m eth yl-1,10-d ia za a n th r a cen e (en tr y 6, Ta ble
All 1H and 13C NMR spectra were recorded either on an
AMX400 spectrometer or an AVANCE400 spectrometer. All
1H chemical shifts are reported in ppm (δ) relative to tetra-
methylsilane and referenced using chemical shifts of residual
solvent resonances (THF-d8, 1.73; C6D6, 7.15). All isolated
quinolines gave satisfactory NMR and mass spectral data.
Gen er a l P r oced u r e for th e Con ver sion of Dia llyla n i-
lin es to Qu in olin es. For the quinolines recorded in Table 1,
a general procedure with 4-methyl-N,N-diallylaniline is as
follows: In a 50-mL round-bottomed flask equipped with a
Teflon seal, 149.0 mg (0.8 mmol) of 4-methyl-N,N-diallylaniline
(Table 1 entry 1), and 27.4 mg of Co2(CO)8 (0.08 mmol) are
added to 5 mL of dry THF in a glovebox. The flask is then
connected to a Schlenk line and any dissolved nitrogen is
removed by freeze-pump-thawing the solution three times.
Carbon monoxide is then introduced at 1 atm and the reaction
is heated in an oil bath at 105 °C for 48 h with stirring. The
solution is then concentrated to ∼1 mL and chromatographed,
using 0-10% ethyl acetate in hexane. The isolated yield of
2-ethyl-3,6-dimethylquinoline as a colorless viscous liquid was
86.5 mg.
Gen er a l P r oced u r e for th e Cr oss-Cou p lin g of Im in es
w ith Dia llyla n ilin es. For the cross-coupling of imines with
diallylanilines (results recorded in Tables 2 and 3), a general
procedure using entry 1 in Table 3 is as follows: 200 mg (1.02
mmol) of N-(4-methyl)phenylbenzaldehyde imine is added to
10 mL of THF in a 100-mL RB flask equipped with a Teflon
seal in a glovebox. To this is added 134.0 mg (0.71 mmol) of
4-methyl-N,N-diallylaniline followed by 35.1 mg of Co2CO8 (0.1
mmol) with stirring. The flask is then connected to a Schlenk
line and the solution is freeze-pump-thawed three times. CO
is introduced at 1 atm and the reaction is heated at 100 °C in
an oil bath for 48 h. The reaction volume is then concentrated
to ∼1 mL, 0.5 g of silica is added, and the solvent is pumped
dry. The crude sample on silica is then chromatographed with
0-10% ethyl acetate in hexane. The isolated yield of 3,6-
dimethyl-2-phenylquinoline as a yellow oil was 145.3 mg
2-Eth yl-3,6-d im eth ylqu in olin e (en tr y 1, Ta ble 1). 1H
NMR: δ 8.17 (d, 1H, J ) 8.4 Hz), 7.29 (s, 1H), 7.18 (s, 1H),
7.14 (d, 1H, J ) 8.4 Hz), 2.71 (q, 2H, J ) 7.6 Hz), 2.18 (s, 3H),
1.96 (s, 3H), 1.40 (t, 3H, J ) 7.6 Hz). 13C NMR: δ 161.80,
146.28, 135.10, 134.70, 130.55, 129.48, 129.42, 128.32, 125.96,
29.25, 21.52, 18.95, 12.37. MS: m/e 185, 184 (bp), 157, 142,
128, 102, 77, 63. Oily liquid.
1
1). H NMR: δ 9.39 (s, 1H), 8.61 (s, 1H), 8.53 (d, 1H, J ) 7.6
Hz), 8.18 (dd, 1H, J ) 8.0, 1.6 Hz), 7.73 (m, 2H), 3.04 (q, 2H,
J ) 7.6 Hz), 2.62 (s, 3H), 1.41 (t, 3H). 13C NMR: δ 166.19,
156.64, 146.39, 142.50, 136.89, 132.30, 132.16, 130.80, 129.35,
128.55, 125.52, 124.40, 31.19, 21.74, 14.19. MS: m/e 222, 221
(bp), 197, 182, 63. Oily liquid.
3-Eth yl-2-p r op ylqu in olin e (en tr y 7, Ta ble 1). 1H NMR:
δ 7.92 (d, 1H, J ) 8.8 Hz), 7.91 (s, 1H), 7.74 (d, 1H, J ) 8.0
Hz), 7.56 (dd, 1H, J ) 8.0, 7.6 Hz), 7.41 (dd, 1H, J ) 8.0, 7.6
Hz), 2.95 (t, 2H, J ) 7.6 Hz), 2.84 (q, 2H, J ) 7.2 Hz), 1.91
(pentet, 2H, J ) 7.6 Hz), 1.32 (t, 3H, J ) 7.2 Hz), 1.06 (t, 3H,
J ) 7.2 Hz). 13C NMR: δ 166.74, 152.55, 140.99, 138.88,
134.54, 133.50, 133.21, 132.51, 130.94, 42.85, 30.73, 27.44,
19.54, 19.45. MS: m/e 199, 184, 171 (bp), 156, 143, 128, 102,
77, 51. Liquid.
3-Ben zyl-2-(2-p h en yleth yl)qu in olin e (en tr y 8, Ta ble 1).
1H NMR: δ 8.01 (d, 1H, J ) 8.Hz), 7.79 (s, 1H), 7.73 (d, 1H, J
) 8.0 Hz), 7.66 (t, 1H, J ) 7.2 Hz), 7.48 (t, 1H, J ) 7.2 Hz),
7.39-7.13 (m, 10H), 4.11 (s, 2H), 3.18 (t, 2H, J ) 6.4 Hz), 3.06
(t, 2H, J ) 6.4 Hz). 13C NMR: δ 163.28, 144.43, 141.70, 138.38,
134.88, 131.14 (2 overlapping peaks), 130.84 (2 peaks), 130.74
(2 peaks), 130.50 (2 peaks), 129.37, 129.35, 128.63, 128.05,
40.83, 39.70, 36.94. MS: m/e 323, 322 (bp), 232, 91. Liquid.
3,9-Dieth yl-2,8-d im eth yl-4,10-d ia za ch r ysen e (en tr y 9,
1
Ta ble 1). H NMR: δ 9.92 (d, 2H, J ) 8.8 Hz), 7.76 (d, 2H, J
) 8.8 Hz), 7.43 (s, 1H), 2.90 (q, 2H, J ) 7.2 Hz), 2.05 (s, 6H),
1.57 (t, 6H, J ) 7.2 Hz). 13C NMR: δ 161.32, 144.49, 136.10,
132.03, 129.87, 126.44, 125.60, 123.34, 29.45, 18.78, 12.50.
MS: m/e 314 (bp), 313, 298, 286, 207, 156, 143. Brown solid.
N-Allyl-2-eth ylben zim id a zole (en tr y 10, Ta ble 1). 1H
NMR: δ 7.55 (m, 1H), 7.27 (m, 1H), 7.09 (m, 2H), 6.01 (m,
1H), 5.12 (d, 1H, J ) 10.4 Hz), 4.89 (d, 1H, J ) 17.2 Hz), 4.79
(d, 2H, J ) 4.8 Hz), 2.82 (q, 2H, J ) 7.6 Hz), 1.39 (t, 3H, J )
7.6 Hz). 13C NMR: δ 149.18, 141.36, 138.96, 133.87, 126.57,
124.74, 121.41, 114.75, 50.76, 26.03, 16.78. MS: m/e 186 (bp),
171, 157, 145, 132, 92, 77, 51.
2-(4-Meth ylp h en yl)-3-m eth ylqu in olin e (en tr y 1, Ta ble
1
2). H NMR: δ 8.06 (s, 1H), 7.99 (d, 1H, J ) 8.4 Hz), 7.61 (t,
1H), J ) 7.2 Hz), 7.55 (d, 2H, J ) 7.6 Hz), 7.47 (t, 1H, J ) 7.2
Hz), 7.27 (d, 2H, J ) 7.6 Hz), 2.50(s, 3H), 2.36(s, 3H). 13C
NMR: δ 160.89, 146.96, 138.33, 137.01, 129.69, 129.59, 129.30,
129.13, 129.00, 127.5, 127.05, 127.00, 126.61, 21.67, 21.06.
MS: 233, 232 (bp), 217, 115, 108, 89, 63. Oily liquid.
2-Eth yl-3,5,7-tr im eth ylqu in olin e (en tr y 2, Ta ble 1). 1H
NMR: δ 8.02 (s, 1H), 7.61 (s, 1H), 6.86 (s, 1H), 2.78 (q, 2H, J
) 7.6 Hz), 2.31 (s, 3H), 2.20 (s, 3H), 2.03 (s, 3H), 1.44 (t, 3H,
J ) 7.6 Hz). 13C NMR: δ 162.14, 148.29, 137.72, 133.09,
131.69, 128.67, 127.97, 127.33, 125.07, 29.30, 21.72, 19.18,
18.50, 12.48. MS: m/e 199, 198 (bp), 171, 128, 115, 91, 77.
White solid. Anal. Calcd: C 84.36; H 8.60; N 7.03. Found: C
84.40; H 8.57; N 7.01.
2-(2-Meth ylp h en yl)-3-m eth ylqu in olin e (en tr y 2, Ta ble
1
2). H NMR: δ 8.09 (s, 1H), 7.97 (d, 1H, J ) 8.4 Hz), 7.82 (d,
1H, J ) 8.0 Hz), 7.62 (t, 1H, J ) 8.0 Hz), 7.50 (t, 1H, J ) 8.0
Hz), 7.30-7.19 (m, 4H), 2.46 (s, 3H), 2.08 (s, 3H). 13C NMR:
δ 166.87, 152.63, 146.77, 141.29, 141.16, 135.61, 135.35,
135.07, 134.03, 133.91, 133.59, 133.36, 132.47, 131.81, 131.09,
24.58, 24.46. MS: m/e 233, 232, 218 (bp), 113, 108, 89, 63. Oily
liquid.
5-Ch lor o-2-eth yl-3,8-d im eth ylqu in olin e (en tr y 3, Ta ble
1
1). H NMR: δ 8.21 (s, 1H), 7.42 (d, 1H, J ) 7.6 Hz), 7.39 (d,
1H, J ) 7.6 Hz), 3.0 (q, 2H, J ) 7.2 Hz), 2.73 (s, 3H), 2.52 (s,
3H), 1.42 (t, 3H). 13C NMR: δ 167.69, 141.90, 137.32, 136.32,
133.49, 133.18, 130.89, 34.39, 23.85, 22.67, 16.93. MS: m/e 219,
218 (bp), 191, 168, 154, 127, 102, 90, 77. Light yellow solid.
6-Cycloh exyl-2-eth yl-3-m eth ylqu in olin e (en tr y 4, Table
2-(4-Meth oxyph en yl)-3-m eth ylqu in olin e (en tr y 3, Table
1
2). H NMR: δ 8.05 (s, 1H), 7.98 (d, 1H, J ) 8.4 Hz), 7.78 (d,
1H, J ) 8.0 Hz), 7.62 (d, 2H, J ) 8.4 Hz), 7.60 (t, 1H, J ) 8.0
Hz), 7.46(t, 1H, J ) 8.0 Hz), 7.00 (d, 2H, J ) 8.4 Hz), 3.85 (s,
3H), 2.52 (s, 3H). 13C NMR: δ 165.68, 165.29, 152.83, 142.07,
139.36, 136.22, 135.02, 134.75, 133.88, 133.24, 132.28, 131.54,
118.82, 60.30, 25.95. MS: m/e 249, 248 (bp), 233, 218, 204,
124, 102, 89, 63. Oily liquid.
1
1). H NMR: δ 8.26 (d, 1H, J ) 8.8 Hz), 7.38 (s, 1H), 7.33 (d,
1H, J ) 1.6 Hz), 7.26 (dd, 1H, J ) 8.8, 1.6 Hz), 2.75 (q, 2H, J
) 7.6 Hz), 2.45 (m, 1H), 2.00 (s, 3H), 1.85-1.69 (m, 5H), 1.42
(t, 3H), 1.40-1.14 (m, 5H). 13C NMR: δ 161.95, 146.73, 145.30,
135.12, 129.58, 129.34, 128.64, 127.85, 123.63, 44.83, 34.77,
2-(2-Meth oxyph en yl)-3-m eth ylqu in olin e (en tr y 4, Table
1
2). H NMR: δ 7.98 (s, 1H), 7.96 (d, 1H, J ) 8.0 Hz), 7.79 (d,
J . Org. Chem, Vol. 68, No. 9, 2003 3567

J acob and J ones
1H, J ) 8.0 Hz), 7.59 (t, 1H, J ) 7.6 Hz), 7.47 (t, 1H, J ) 7.6
Hz), 7.39 (t, 1H, J ) 7.2 Hz), 7.29 (d, 1H, J ) 7.2 Hz), 7.05 (m,
2H), 3.74 (s, 3H), 2.28 (s, 3H). 13C NMR: δ 164.91, 162.78,
152.70, 140.21, 136.74, 136.60, 136.11, 135.11, 134.96, 133.64,
133.54, 132.34, 131.58, 126.06, 116.29, 60.36, 24.19. MS: m/e
249, 248 (bp), 233, 218, 204, 124, 102, 89, 63. Oily liquid.
Hz), 7.49 (s, 1H), 7.33-7.22 (m, 4H), 6.80 (d, 1H), 3.44 (s, 3H),
2.26 (s, 3H). 13C NMR: δ 163.75, 163.05, 148.87, 147.23,
141.07, 136.46, 134.91, 134.79, 134.39, 133.40, 133.25, 126.82,
109.75, 60.55, 25.73. MS: m/e 249, 248 (bp), 217, 205, 124,
102, 77. Yellow solid.
3,5,7-Tr im eth yl-2-p h en ylqu in olin e (en tr y 4, Ta ble 3).
1H NMR: δ 8.02 (s, 1H), 7.73 (s, 1H), 7.66 (d, 2H, J ) 8.0 Hz),
7.24 (t, 2H, J ) 8.0 Hz), 7.16 (t, 1H, J ) 7.6 Hz), 6.88 (s, 1H),
2.31 (s, 3H), 2.19 (s, 3H), 2.18 (s, 3H). 13C NMR: δ 159.87,
148.35, 142.03, 138.33, 133.18, 129.79, 129.41, 128.26, 128.15,
127.98, 127.85, 127.64, 125.38, 21.75, 20.94, 18.47. MS: m/e
247, 246 (bp), 230, 216, 122, 115, 102, 77, 63. Light yellow solid.
Anal. Calcd: C 87.40; H 6.93; N 5.67. Found: C 87.24; H 6.96;
N 5.70.
1
3-Meth yl-2-(4-p yr id yl)qu in olin e (en tr y 5, Ta ble 2). H
NMR: δ 8.76 (dd, 2H, J ) 4.8, 1.2 Hz), 8.09 (d, 1H, J ) 8.8
Hz), 8.05 (s, 1H), 7.81 (m, 1H), 7.69 (t, 1H, J ) 6.8 Hz), 7.54
(m, 3H), 2.47 (s, 3H). 13C NMR: δ 157.82, 149.96, 148.97,
146.97, 137.65, 129.69, 129.64, 129.58, 128.90, 128.22, 127.48,
127.17, 20.59. MS: m/e 220, 219 (bp), 192, 110, 95, 83. Oily
liquid.
2-(4-(Dim eth yla m in o)p h en yl)-3-m eth ylqu in olin e (en -
1
tr y 7, Ta ble 2). H NMR: δ 7.99 (s, 1H), 7.97 (d, 1H, J ) 7.6
6-Ch lor o-3-m eth yl-4-p h en ylqu in olin e (en tr y 5, Ta ble
1
Hz), 7.74 (d, 1H, J ) 7.6 Hz), 7.60 (m, 3H), 7.42(t, 1H, J ) 6.8
Hz), 6.81 (d, 2H, J ) 8.8 Hz), 3.00 (s, 6H), 2.55 (s, 3H). 13C
NMR: δ 165.68, 156.28, 152.96, 141.95, 135.97, 134.95, 134.80,
133.69, 133.01, 132.23, 131.12, 117.08, 45.33, 26.30. MS: m/e
262, 261 (bp), 245, 217, 130, 108, 89, 63. Oily liquid.
3). H NMR: δ 8.04 (s, 1H), 8.00 (d, 1H, J ) 4.8 Hz), 7.80 (s,
1H), 7.63 (m, 3H), 7.45 (m, 3H), 2.49 (s, 3H). 13C NMR: δ
166.21, 151.07, 146.65, 141.36, 137.32, 136.92, 136.07, 134.90,
134.84, 134.05, 133.77, 133.55, 131.16, 25.74. MS: m/e 253,
252 (bp), 217, 207, 125, 108, 79, 63. Yellow solid.
3-Meth yl-2-(1-n a p h th yl)qu in olin e (en tr y 8, Ta ble 2). 1H
NMR: δ 8.15 (s, 1H), 8.02 (d, 1H, J ) 8.4 Hz), 7.95 (d, 2H, J
) 8.4 Hz), 7.88 (d, 1H, J ) 8.0 Hz), 7.64 (t, 1H), 7.58-7.34 (m,
6H), 2.18 (s, 3H). 13C NMR: δ 165.90, 152.77, 144.91, 141.34,
139.57, 137.46, 136.22, 135.23, 134.08, 133.97, 133.79, 133.74,
132.57, 132.05, 131.90, 131.75, 131.40, 131.26, 130.90, 24.68
ppm. MS: m/e 269, 268 (bp), 267, 253, 133, 89, 63. Oily liquid.
6-(Dim eth yla m in o)-3-m eth yl-2-p h en ylqu in olin e (en tr y
9, Ta ble 2). 1H NMR: δ 8.22 (d, 1H, J ) 9.2 Hz), 7.70 (m,
2H), 7.47 (s, 1H), 7.24 (m, 2H), 7.17 (m, 1H), 6.97 (dd, 1H, J )
9.2, 2.8 Hz), 6.61 (d, 1H, J ) 2.4 Hz), 2.52 (s, 6H), 2.21 (s,
3H). 13C NMR: δ 156.49, 148.86, 142.34, 142.16, 135.05,
130.85, 129.88, 129.60, 129.26, 128.21, 127.78, 119.07, 104.55,
40.37, 20.90. Oily liquid. MS: m/e 262, 261 (bp), 245, 217, 202,
130, 122, 96, 63. Anal. Calcd: C 82.39; H 6.92; N 10.69.
Found: C 82.46; H 7.02; N 10.52.
3-Meth yl-2,6-d ip h en ylqu in olin e (en tr y 6, Ta ble 3). H
1
NMR: δ 8.33 (d, 1H, J ) 8.8 Hz), 7.72 (d, 1H, J ) 1.6 Hz),
7.66-7.63 (m, 3H), 7.53 (m, 2H), 7.47 (s, 1H), 7.25-7.11 (m,
6H), 2.14 (s, 3H). 13C NMR: δ 160.51, 147.13, 141.76, 141.23,
139.40, 137.00, 130.64, 129.74, 129.59, 129.22, 128.76, 128.20,
128.09, 127.97, 127.61, 127.17, 124.82, 20.77. MS: m/e 295,
294 (bp), 207, 147, 115, 77, 51. White solid. Anal. Calcd: C
89.45; H 5.81; N 4.75. Found: C 88.88; H 5.87; N 4.87.
R ea ct ion of N-P h en yl-4-(d im et h yla m in o)b en za ld e-
h yd e Im in e (Ta ble 2, en tr y 7) w ith Co2(CO)8 a n d CO. In
an NMR experiment, 11.6 mg of the imine was dissolved in
0.7 mL of THF-d8 and 10.0 mg of Co2(CO)8 (0.5 equiv), in a
glovebox. The reaction mixture was freeze-pump-thawed
three times to remove any dissolved nitrogen and then CO was
introduced at 1 atm. The sample was heated in an oil bath at
120 °C. Complete consumption of starting material to form a
single product was observed when followed by NMR in two
weeks. This product was isolated by using preparative TLC
and identified as 6-(dimethylamino)-N-phenylphthalimidine.
1H NMR: δ 7.86 (m, 2H, J ) 8.8 Hz), 7.40 (m, 2H), 7.32 (d,
1H, J ) 8.4 Hz), 7.18 (d, 1H, J ) 2.4 Hz), 7.14 (m, 1H), 6.95
(dd, 1H, J ) 8.4, 2.4 Hz), 4.74 (s, 2H), 3.00 (s, 6H). 13C NMR:
δ 168.62, 151.34, 140.23, 134.45, 129.41, 128.13, 124.49,
123.26, 119.70, 117.29, 106.79, 50.59, 41.17. MS: m/e 252 (bp),
251, 224, 208, 89, 77, 51.
3-Meth yl-2-p h en y-6-(N-p h en yla m in o)qu in olin e (en tr y
1
10, Ta ble 2). H NMR: δ 7.85 (d, 1H, J ) 10.0 Hz), 7.84 (s,
1H), 7.68 (s, br, 1H), 7.63 (m, 2H), 7.45-7.37 (m, 5H), 7.34-
7.20 (m, 4H), 6.90 (m, 1H), 2.44 (s, 3H). 13C NMR: δ 162.31,
149.09, 148.69, 147.94, 147.40, 140.43, 136.07, 134.90, 134.78,
134.67, 133.33, 133.08, 127.97, 126.48, 123.87, 119.75, 113.27,
25.73. MS: m/e 310 (bp), 309, 217, 154, 77, 51. Yellow solid.
6-Cycloh exyl-3-m eth yl-2-p h en ylqu in olin e (en tr y 11,
1
Ta ble 2). H NMR: δ 8.29 (d, 1H, J ) 8.8 Hz), 7.63 (d, 2H, J
) 7.2 Hz), 7.50 (s, 1H), 7.35 (s, 1H), 7.29-7.15 (m, 4H), 2.46
(m, 1H), 2.16 (s, 3H), 1.86-1.71 (m, 5H), 1.39-1.25 (m, 5H).
13C NMR: δ 159.74, 146.80, 146.18, 141.97, 136.54, 130.08,
129.77, 129.23, 129.03, 128.33, 128.26, 128.14, 123.58, 44.87,
34.71, 27.25, 26.55, 20.76. MS: m/e 301, 300 (bp), 281, 244,
207, 115, 96, 73. White solid.
Scr een in g of Oth er Or ga n om eta llic Com p ou n d s. The
following complexes were screened for catalytic activity and
showed no reaction toward diallylaniline at 120 °C: Ni(cod)2,
(Cy3P)2Ni(CH2dCH2), Mn2(CO)10, Mo(CO)6, (CH3CN)3Mo(CO)3,
(CH3CN)3W(CO)3, (Ph3P)2Ni(CO)2, (Ph3P)2Rh(Cl)(CO), (Ph3P)3-
Ru(Cl)(H)(CO), and Rh6CO16 (cod ) cyclooctadiene, Cy )
cyclohexyl).
Complexes (Ph3P)3Rh(H)(CO), Ru3(CO)12, and [(cod)RhCl]2
led to a complex mixture of reaction products at 120 °C. When
[(dippe)NiH]2 [dippe ) 1,2-bis(diisopropylphosphino)ethane]
was reacted with diallylaniline (1:1), a nickel-olefin complex
was formed at both double bonds. This complex decomposed
on heating at 100 °C. Complexes [(Ph3P)3Co(CH2CH2)]2 and
(Ph3P)3Co(H)(N2) caused isomerization of both double bonds
to the enamine in a fast reaction when treated with diallyl-
aniline.
6-ter t-Bu t yl-3-m et h yl-2-p h en ylq u in olin e (en t r y 12,
1
Ta ble 2). H NMR: δ 8.04 (s, 1H), 7.93 (d, 1H, J ) 8.8 Hz),
7.76 (d, 1H, J ) 8.8 Hz), 7.75 (s, 1H), 7.63 (d, 2H, J ) 8.0 Hz),
7.46-7.38 (m, 3H), 2.48 (s, 3H), 1.44 (s, 9H). 13C NMR: δ
164.97, 154.54, 151.39, 147.23, 142.19, 134.89, 134.69, 134.42,
133.40, 133.37, 133.11, 132.91, 127.32, 40.38, 36.39, 25.70.
MS: m/e 275, 274 (bp), 260, 2245, 231, 217, 115. White solid.
3,8-Dim eth yl-2-p h en ylqu in olin e (en tr y 14, Ta ble 2). 1H
NMR: δ 8.05 (s, 1H), 7.67-7.63 (m, 3H), 7.49-7.36 (m, 5H),
2.75 (s, 3H), 2.51 (s, 3H). 13C NMR: δ 164.35, 151.62, 147.39,
142.85, 142.55, 134.98, 134.36, 134.16, 133.46, 133.42, 133.34,
131.67, 130.39, 25.60, 22.87. MS: m/e 233, 232 (bp), 217, 127,
115, 102, 77, 63. Oily liquid.
Ack n ow led gm en t is made to the National Science
Foundation (CHE-9616601) for their support of this
work.
1
3,6-Dim eth yl-2-p h en ylqu in olin e (en tr y 1, Ta ble 3). H
NMR: δ 8.22 (d, 1H, J ) 8.8 Hz), 7.61 (m, 2H), 7.44 (s, 1H),
7.24-7.13 (m, 5H), 2.18 (s, 3H), 2.14 (s, 3H).13C NMR:
δ
Su p p or tin g In for m a tion Ava ila ble: A description of the
kinetics of the reaction of diallylaniline with Co2(CO)8. This
material is available free of charge via the Internet at
http://pubs.acs.org.
159.70, 146.40, 141.90, 136.16, 136.09, 131.17, 129.92, 129.74,
129.18, 128.26, 128.15, 128.09, 125.91, 21.61, 20.75. MS: m/e
233, 232 (bp), 115, 89, 77, 63. Oily liquid.
6-Meth oxy-3-m eth yl-2-p h en ylqu in olin e (en tr y 3, Ta ble
1
3). H NMR: δ 8.27 (d, 1H, J ) 9.2 Hz), 7.72 (d, 2H, J ) 7.6
J O026737J
3568 J . Org. Chem., Vol. 68, No. 9, 2003