Palladium-Catalyzed Annulation of Internal Alkynes by Arene-Containing Vinylic Iodides and Triflates

Article abstract of DOI:10.1021/jo972154b

In the presence of a palladium catalyst, internal alkynes undergo carboannulation by cyclic and acyclic vinylic iodides and triflates bearing a neighboring aromatic ring to produce a variety of carbocycles. For example, a number of 9,10-disubstituted-1,2,3,4-tetrahydrophenanthrenes have been prepared in good yields through the palladium-catalyzed annulation of internal alkynes by 2-phenyl-1-cyclohexenyl triflate (1) or l-iodo-2-phenylcyclohexene (2). This annulation process is fairly general and highly regioselective. The process appears to involve oxidative addition of the vinylic substrate to Pd(0) to produce a vinylic palladium intermediate, which adds the carbon moiety to the less hindered end and the palladium to the more hindered end of the alkyne, followed by intramolecular ring closure onto the neighboring aryl group. The scope and limitations of this methodology are discussed.

Full text of DOI:10.1021/jo972154b

2002
J . Org. Chem. 1998, 63, 2002-2009
P a lla d iu m -Ca ta lyzed An n u la tion of In ter n a l Alk yn es by
Ar en e-Con ta in in g Vin ylic Iod id es a n d Tr ifla tes
Richard C. Larock* and Qingping Tian
Department of Chemistry, Iowa State University, Ames, Iowa 50011
Received November 25, 1997
In the presence of a palladium catalyst, internal alkynes undergo carboannulation by cyclic and
acyclic vinylic iodides and triflates bearing a neighboring aromatic ring to produce a variety of
carbocycles. For example, a number of 9,10-disubstituted-1,2,3,4-tetrahydrophenanthrenes have
been prepared in good yields through the palladium-catalyzed annulation of internal alkynes by
2-phenyl-1-cyclohexenyl triflate (1) or 1-iodo-2-phenylcyclohexene (2). This annulation process is
fairly general and highly regioselective. The process appears to involve oxidative addition of the
vinylic substrate to Pd(0) to produce a vinylic palladium intermediate, which adds the carbon moiety
to the less hindered end and the palladium to the more hindered end of the alkyne, followed by
intramolecular ring closure onto the neighboring aryl group. The scope and limitations of this
methodology are discussed.
In tr od u ction
9,10-disubstituted phenanthrenes has been achieved by
the coupling of simple aryl iodides and diarylacetylenes.6
Grigg has synthesized polycyclic aromatics by the in-
tramolecular coupling of aryl halides bearing alkyne
units.7
The transition-metal mediated annulation of alkynes
has proven useful for the synthesis of a variety of hetero-
and carbocyclic ring systems.1 Methodology based on
palladium is of special value, since the palladium com-
plexes are readily available, generally not oxygen or
moisture sensitive, and accommodate a number of dif-
ferent functional groups.2
Heck first reported the synthesis of 9,10-diphe-
nylphenanthrene from 2-iodobiphenyl and diphenylacet-
ylene by a palladium-catalyzed annulation process; how-
ever, the yield was only 14% (eq 1).3 We have recently
optimized reaction conditions and extended this process
to a wide variety of iodobiaryls and internal alkynes.4
Merlic and McInnes simultaneously demonstrated that
substituted indolocarbazoles can be formed by this same
palladium-catalyzed cross-coupling of biindolyl iodides
and internal alkynes.5
Recently, convenient palladium-alkyne annulation
methodology has been developed in this group, which
offers useful routes to indoles,8 indenones,9 benzofurans
and isocoumarins (eq 2).10
All of this previous methodology utilizes aryl iodides
to annulate internal alkynes to give the desired products.
This methodology would be still more useful if it could
be expanded to vinylic iodides and triflates.11 In this
paper, we report the regioselective annulation of internal
alkynes by cyclic and acyclic vinylic iodides and triflates
bearing neighboring aryl groups, which leads to the
synthesis of derivatives of 1,2,3,4-tetrahydrophenan-
threne,12 7H-benzo[c]fluoren-7-one,13 7H-benzo[c]xanthen-
7-one,14 and naphthalene.15
(6) Dyker, G.; Kellner, A. Tetrahedron Lett. 1994, 35, 7633.
(7) (a) Grigg, R.; Loganathan, V.; Sridharan, V. Tetrahedron Lett.
1996, 37, 3399. (b) Brown, D.; Grigg, R.; Sridharan, V.; Tambyrajah,
V. Tetrahedron Lett. 1995, 36, 8137. (c) Grigg, R.; Kennewell, P.;
Teasdale, A.; Sridharan, V. Tetrahedron Lett. 1993, 34, 153.
(8) Larock, R. C.; Yum, E. K. J . Am. Chem. Soc. 1991, 113, 6689.
(9) Larock, R. C.; Doty, M. J .; Cacchi, S. J . Org. Chem. 1993, 58,
4579.
Polycyclic aromatic hydrocarbons have also been pre-
pared by other palladium-catalyzed processes involving
aryl halides and alkynes. For example, the synthesis of
(1) (a) Schore, N. E. Chem. Rev. 1988, 88, 1081. (b) Ojima, I.;
Tzamarioudaki, M.;Li, Z.; Donovan, R. T. Chem. Rev. 1996, 96, 635.
(2) (a) Pfeffer, M. Recl. Trav. Chim. Pays-Bas 1990, 109, 567. (b)
Pfeffer, M.; Spencer, J .; Decian, A.; Fisher, J . J . Org. Chem. 1995, 60,
1005.
(3) Wu, G.; Rheingold, A. L.; Geib, S. J .; Heck, R. F. Organometallics
1987, 6, 1941.
(4) (a) Larock, R. C.; Doty, M. J .; Tian, Q.; Zenner, J . M. J . Org.
Chem. 1997, 62, 2, 7536. (b) Larock, R. C.; Zenner, J . M. Full paper to
be published.
(10) Larock, R. C.; Yum, E. K.; Doty, M. J .; Sham, K. K. C. J . Org.
Chem. 1995, 60, 3270.
(11) For a preliminary communication, see ref 4a.
(12) (a) Song, C.; Hanaoka, K.; Ono, T.; Nomura, M. Bull. Chem.
Soc. J pn. 1988, 61, 3788. (b) Morin, F. G.; Horton, W. J .; Grant, D.
M.; Pugmire, R. J .; Dalling, D. K. J . Org. Chem. 1985, 50, 3380.
(13) (a) Fu, J .; Zhao, B.; Sharp, M. J .; Snieckus, V. J . Org. Chem.
1991, 56, 1683. (b) Streitwieser, A., J r.; Brown, S. M. J . Org. Chem.
1988, 53, 904.
(14) Kamat, S. P.; Paknikar, S. K. Ind. J . Chem., Sec. B 1988, 27B,
773.
(5) Merlic, C. A.; McInnes, D. M. Tetrahedron Lett. 1997, 38, 7661.
S0022-3263(97)02154-3 CCC: $15.00 © 1998 American Chemical Society
Published on Web 02/26/1998

Palladium-Catalyzed Annulation of Internal Alkynes
J . Org. Chem., Vol. 63, No. 6, 1998 2003
Resu lts a n d Discu ssion
Fortunately, the yield can be improved by simply in-
creasing the steric bulk of the silyl group. For example,
1-phenyl-2-(triethylsilyl)acetylene (entries 11 and 12,
Table 1) afforded a significantly better yield than 1-phen-
yl-2-(trimethylsilyl)acetylene (entries 13-15, Table 1).
We initiated our studies on vinylic systems by employ-
ing compound 1 as the starting material (eq 3, X ) OTf).
Two procedures have been developed for the annulation
Compound 2, the iodide corresponding to triflate 1, has
also been employed in this annulation process in order
to compare the results using an iodide and a triflate
under similar reaction conditions (eq 3, X ) I). It was
found that vinylic iodide 2 provided very similar yields
and mixtures of regioisomers to compound 1. Thus, cyclic
vinylic iodides appear to be as reactive and versatile as
cyclic vinylic triflates in the annulation process.
The yield for the annulation of 1-phenyl-2-(trimethyl-
silyl)acetylene (entries 13 and 14, Table 1) by 2 was
improved by replacing n-Bu4NCl (3 equiv) with LiCl (1
equiv). It may be that the ammonium salt facilitates
desilylation, but note that less LiCl was necessary to get
comparable yields.
of internal alkynes by this triflate: procedure A, 5 mol %
Pd(OAc)2, 2 equiv of NaOAc, 3 equiv of n-Bu4NCl in DMF
at 100 °C; and procedure B, 5 mol % Pd(OAc)2, 2 equiv
of NaOAc, 1 equiv of LiCl in DMF at 100 °C. An excess
of the alkyne (2 equiv) has generally been employed. Our
results are summarized in Table 1.
The triflate annulation process works best for alkynes
containing hindered groups, such as phenyl, tert-butyl,
and trialkylsilyl groups. Without these hindered groups,
alkynes such as 1-phenyl-1-propyne, 1-phenyl-1-butyne,
and 4-octyne gave inseparable mixtures containing sev-
eral products. It was also noticed that alkynes bearing
an electron-withdrawing group directly on the triple bond
afforded poor results. For example, ethyl phenylpropi-
olate did not give the desired product.
The annulation of unsymmetrical alkynes has proven
to be highly regioselective in most cases, providing only
the regioisomers shown in Table 1. The regiochemistry
has been assigned based on all of our previous work on
these types of alkyne annulations in which the aryl or
vinylic group has always added to the less hindered end
of the alkyne.8-10 The regiochemistry of the product
shown in entry 4 of Table 1 has been confirmed by 2D
NOESY.16 The 2D NOESY spectrum of 9-tert-butyl-10-
phenyl-1,2,3,4-tetrahydrophenanthrene (Figure 1 and
entry 4, Table 1) showed a cross-peak between H-15 and
H-8 and a cross-peak between H-15 and H-12, but none
between H-15 and H-1. 2D NOESY cross-peaks were
also observed between H-4 and H-5, and between H-1
and H-12. These 2D NOESY cross-peaks are totally
consistent with the structure shown in Figure 1. The
regiochemistry of this process thus follows the pattern
established in our previous research in which the organic
moiety of the organopalladium intermediate (see the later
mechanistic discussion) adds to the less hindered end of
the alkyne and the palladium moiety to the more
hindered end.8-10
This annulation reaction appears to proceed by the
following mechanism: (1) reduction of Pd(OAc)2 to the
actual catalyst Pd(0), (2) oxidative addition of the vinylic
triflate or iodide to Pd(0) to produce a vinylic palladium
intermediate, (3) vinylpalladium coordination to the
alkyne and subsequent insertion to form a new vinylpal-
ladium intermediate, (4) either oxidative addition of the
resulting vinylpalladium intermediate to the neighboring
aryl C-H bond to form a palladium(IV) intermediate18
(path 1) and subsequent HX (X ) OTf or I) elimination
by base, or electrophilic palladation19 of the arene (path
2), and finally (5) reductive elimination of the product
with concomitant regeneration of the Pd(0) catalyst
(Scheme 1). All steps are well precedented in organo-
palladium chemistry.
To determine the scope and limitations of this process,
this annulation methodology has been applied to a
number of other interesting vinylic iodides and triflates.
The reaction of 2-iodo-3-phenylcyclohex-2-enone (3) af-
forded 3-hydroxybiphenyl in high yield, regardless of the
alkyne used (entries 18 and 19, Table 1). No annulation
products were observed. However, the reaction of diphe-
nylacetylene and 2-iodo-3-phenylcyclohex-2-enol, ob-
tained by the reduction of 3, afforded the desired annu-
lation product, 1-hydroxy-9,10-diphenyl-1,2,3,4-tetrahydro-
phenanthrene, in 51% yield (entry 20, Table 1).
As shown in entry 21 of Table 1, 5,6-diphenyl-7H-
benzo[c]fluoren-7-one was obtained in 54% yield from the
reaction of 2-iodo-3-phenylindenone and diphenylacet-
ylene. On the other hand, the reaction of 3-iodoflavone
and diphenylacetylene afforded the desired product, 5,6-
diphenyl-7H-benzo[c]xanthen-7-one, in only 25% yield.
The major product was in fact 3-benzoyl-2-(2-hydrox-
yphenyl)-4,5-diphenylfuran isolated in 61% yield. This
product apparently arises by alkyne insertion and sub-
sequent electrophilic attack of the vinylpalladium inter-
mediate on the carbonyl oxygen, followed by opening of
the pyrone ring. Conjugation from the oxygen of the
The silyl-substituted products produced by this process
(entries 11-15, Table 1) have special synthetic value,
since the silyl group can be easily converted to other
functional groups.17 It was noticed, however, that reac-
tions of alkynes with trialkylsilyl groups did not offer
particularly high yields. This may be due to desilylation
of the starting alkyne or the product during the reaction.
(15) (a) Donaldson, N. The Chemistry and Technology of Naphtha-
lene Compounds; Edward Arnold Ltd.: London, 1958. (b) Amer, I.;
Blume, J .; Vollhardt, K. P. C. J . Mol. Catal. 1990, 60, 323.
(16) J eener, J .; Meier, B. H.; Bachmann, P.; Ernst, R. R. J . Chem.
Phys. 1979, 71, 4546.
(17) (a) Chan, T. H.; Fleming, I. Synthesis 1979, 761. (b) Patai, S.;
Rappoport, Z. The Chemistry of Organic Silicon Compounds; J ohn
Wiley & Sons: New York, 1989.
(18) (a) Gonza´lez, J . J .; Garc´ıa, N.; Go´mez-Lor, B.; Echavarren, A.
M. J . Org. Chem. 1997, 62, 1286. (b) Pogodin, S.; Biedermann, P. U.;
Agranat, I. J . Org. Chem. 1997, 62, 2285. (c) Rice, J . E.; Cai, Z.-W. J .
Org. Chem. 1993, 58, 1415. (d) Dyker, G. Chem. Ber./Recueil 1997,
130, 1567.
(19) (a) Ames, D. E.; Bull, D. Tetrahedron 1982, 38, 383. (b)
Catellani, M.; Chiusoli, G. P. J . Organomet. Chem. 1992, 425, 151.
(20) Doty, M. J . Ph.D. Dissertation, Iowa State University, 1995.

2004 J . Org. Chem., Vol. 63, No. 6, 1998
Larock and Tian
Ta ble 1. P a lla d iu m -ca ta lyzed An n u la tion of In ter n a l Alk yn es by Ar en e-con ta in in g Vin ylic Iod id es a n d Tr ifla tes

Palladium-Catalyzed Annulation of Internal Alkynes
J . Org. Chem., Vol. 63, No. 6, 1998 2005
Ta ble 1 (Con tin u ed )
flavone ring is expected to enhance the nucleophilicity
of the carbonyl oxygen. A similar furan-containing
product was obtained from 4,4-dimethyl-2-pentyne (entry
23, Table 1).
Acyclic vinylic iodides and triflates have also been
examined as annulating agents. No annulation products
were obtained from (Z)-1-iodo-2-phenylethylene, perhaps
due to â-hydrogen elimination from the vinylic palladium
intermediate. On the other hand, 2-iodo-1,1-diphenyl-
ethylene, which has no â-hydrogen, afforded the expected
products (entries 24, 26, 28, and 29, Table 1). Although
the regioselectivity for 4,4-dimethyl-2-pentyne was quite
good, a mixture of regioisomers was obtained when 3,3-
dimethyl-1-phenyl-1-butyne was employed (compare en-
tries 26 and 28). For 2-iodo-1,1-diphenylethylene, the
group in the R-position of the vinylic palladium is

2006 J . Org. Chem., Vol. 63, No. 6, 1998
Larock and Tian
2-P h en yl-1-cycloh exen yl Tr ifla te. 2-Phenyl-1-cyclohex-
enyl triflate was prepared according to a literature procedure.25
To a suspension of NaH (60% in mineral oil, 0.92 g, 22.9 mmol)
in 30 mL of DMF at room temperature was added dropwise
2-phenylcyclohexanone (2.0 g, 12 mmol) in 10 mL of DMF.
After stirring for 2 h under N2, N-phenyltrifluoromethane-
sulfonimide (4.97 g, 13.8 mmol) was added in one portion and
the mixture was stirred overnight, diluted with ether, washed
with satd NH4Cl, water, and brine, dried (MgSO4), and
concentrated. Chromatography (200:1 hexanes/ethyl acetate)
gave a colorless liquid (2.18 g, 60%): 1H NMR (CDCl3) δ 1.80
F igu r e 1. The structure of 9-tert-butyl-10-phenyl-1,2,3,4-
tetrahydrophenanthrene.
(m, 2 H), 1.88 (m, 2 H), 2.50 (m, 4 H), 7.25-7.38 (m, 5 H); 13
C
hydrogen, which may be too small to control the regiose-
lectivity of the addition of the vinylic palladium inter-
mediate to the internal alkyne. Thus, it was expected
that the regioselectivity might be improved were the size
of the R-group to be increased. This was confirmed by
experiment. Only one regioisomer was obtained from the
reaction of 3,3-dimethyl-1-phenyl-1-butyne and 2-iodo-
1,1-diphenylpropene, which has a larger R-substituent
(CH3) (entry 31, Table 1).
Acyclic iodides and triflates (entries 24-31, Table 1),
which are generally not as reactive as cyclic vinylic
iodides and triflates, required longer reaction times and
generally afforded lower yields. While the acyclic tri-
flates appear to be more reactive than the corresponding
iodides, the yields of the annulation products are lower
and different procedures have been employed (compare
entries 24 and 25, and 26 and 27, Table 1). This is in
contrast to the situation for the cyclic systems, where
cyclic triflates afforded the same yields as the corre-
sponding iodides under identical reaction conditions.
NMR (CDCl3) δ 22.1, 23.0, 28.1, 31.3, 118.0, 127.9, 128.1, 128.3,
131.1, 136.9, 143.8; IR (CH2Cl2) 3026, 2942, 1414, 1207 (SdO)
cm-1; HRMS m/z 306.0543 (calcd for C13H13F3O3S, 306.0538).
1-Iod o-2-p h en ylcycloh exen e. 1-Iodo-2-phenylcyclohex-
ene was prepared according to a literature procedure.26
2-Phenyl-1-cyclohexenyl triflate (1.0 g, 3.3 mmol), MgI2 (2.7
g, 9.8 mmol), and Et3N (0.4 g, 3.9 mmol) were placed in 40
mL of cyclohexane. The solution was refluxed at 95 °C for 20
h. After the reaction mixture was allowed to cool, it was
diluted with ether, washed with satd NaHSO3 and water, dried
(MgSO4), filtered, and concentrated. Chromatography (hex-
anes) gave a colorless oil (0.71 g, 77%): 1H NMR (CDCl3) δ
1.75 (m, 2 H), 1.86 (m, 2 H), 2.44 (m, 2 H), 2.79 (m, 2 H), 7.15
(m, 2 H), 7.33 (m, 3 H); 13C NMR (CDCl3) δ 22.9, 25.5, 34.0,
41.5, 98.7, 127.0, 127.8, 128.2, 144.2, 146.9; IR (CH2Cl2) 3019,
2931, 1498 cm-1; HRMS m/z 284.0062 (calcd for C12H13I,
284.0062).
2-Iod o-3-p h en ylcycloh ex-2-en on e. 2-Iodo-phenylcyclo-
hex-2-enone was prepared according to a literature proce-
dure.27 To a solution of 3-phenylcyclohex-2-enone28 (2.0 g, 11.6
mmol)
in
CH2Cl2
(20
mL)
was
added
tri-
methylsilyl azide (3.8 mL, 28.8 mmol) at 0 °C. After the
mixture was stirred at 0 °C for 2 h, a solution of I2 (11.8 g,
46.4 mmol) in CH2Cl2 (30 mL) and pyridine (30 mL) was added
slowly at 0 °C. The mixture was allowed to warm to room
temperature and stirred for 4 days. The resulting mixture was
then diluted with diethyl ether (250 mL). The organic layer
was washed with water (200 mL), HCl (10%, 200 mL), satd
NaHCO3 (200 mL), Na2S2O3 (10%, 200 mL) and brine, and
dried (MgSO4). Filtration, concentration, and recrystallization
from ethanol gave a light orange solid (1.2 g, 3.9 mmol, 33%):
mp 129-131 °C (ethanol); 1H NMR (CDCl3) δ 2.14 (quintet, J
) 6.0 Hz, 2 H), 2.73 (t, J ) 6.0 Hz, 2 H), 2.80 (t, J ) 6.0 Hz,
2 H), 7.24 (m, 2 H), 7.41 (m, 3 H); 13C NMR (CDCl3) δ 27.3,
40.0, 41.0, 111.4, 131.1, 133.0, 133.3, 148.8, 172.2, 197.3; IR
(CH2Cl2) 3054, 2960, 1674 (CdO) cm-1; HRMS m/z 297.9859
(calcd for C12H11IO, 297.9855).
2-Iod o-3-p h en ylcycloh ex-2-en ol. 2-Iodo-3-phenylcyclo-
hexenol was prepared according to a literature procedure.29
To a solution of 2-iodo-3-phenylcyclohex-2-enone (0.2 g, 0.67
mmol) and CeCl3‚7H2O (0.26 g, 0.68 mmol) in MeOH (5 mL)
was added NaBH4 (0.026 g, 0.69 mmol) in one portion with
stirring under Ar. After 10 min, gas evolution ceased and the
reaction was quenched with satd NH4Cl, followed by 5% HCl,
extracted with Et2O, dried over MgSO4, filtered, concentrated,
and purified by chromatography (5:1 hexanes/ethyl acetate).
A white solid (0.19 g, 0.63 mmol, 95%) was obtained: mp 74-
75 °C (CH2Cl2/MeOH); 1H NMR (CDCl3) δ 1.82 (m, 1 H), 1.98
(m, 3 H), 2.27 (d, J ) 4.2 Hz, 1 H), 2.45 (m, 2 H), 4.45 (m, 1
Con clu sion
The palladium-catalyzed annulation of internal alkynes
by arene-containing vinylic iodides and triflates has been
achieved. The generality of this process has been dem-
onstrated by the use of a variety of cyclic and acyclic
iodides and triflates, and internal alkynes. This general-
ity, combined with the high regioselectivity, make this
annulation process an attractive synthetic route to a
range of polycyclic aromatic hydrocarbons.
Exp er im en ta l Section
Gen er a l. All 1H and 13C NMR spectra were recorded at
300 and 75.5 MHz, respectively. 2D COSY and NOESY NMR
spectra were recorded at 400 MHz. Thin-layer chromatogra-
phy (TLC) was performed using commercially prepared 60
mesh silica gel plates (Whatman K6F), and visualization was
effected with short wavelength UV light (254 nm), or basic
KMnO4 solution (3 g KMnO4 + 20 g K2CO3 + 5 mL NaOH
(5%) + 300 mL H2O).
Rea gen ts. All reagents were used directly as obtained
commercially unless otherwise noted. Anhydrous forms of
NaOAc, LiCl, DMF, CH2Cl2, hexanes, and ethyl acetate were
purchased from Fisher-Scientific. Pd(OAc)2 was donated by
J ohnson Mathey, Inc. and Kawaken Fine Chemicals Co., Ltd.
Diphenylacetylene, 1-phenyl-2-(trimethylsilyl)acetylene, and
N-phenyltrifluoromethanesulfonimide were obtained from Al-
drich Chemical Co., Inc. 4-Phenyl-2-methyl-3-butyn-2-ol and
1-(1-butynyl)cyclohexanol were purchased from Farchan Sci-
entific Co. 4,4-Dimethyl-2-pentyne was purchased from Lan-
caster Synthesis Inc. 3,3-Dimethyl-1-phenyl-1-butyne,9 1-phenyl-
2-(triethylsilyl)acetylene,20 and 2-(2-phenylethynyl)-2-methyl-
1,3-dioxolane,21 (Z)-1-iodo-2-phenylethylene,22 2-iodo-1,1-
diphenylethylene,23 and 3-iodoflavone24 were prepared according
to previous literature procedures. The following starting
materials were prepared.
(22) Dieck, H. A.; Heck, R. F. J . Org. Chem. 1975, 40, 1083.
(23) Curtin, D. Y.; Flynn, E. W. J . Am. Chem. Soc. 1959, 81, 4714.
(24) Costa, A. M. B. S. R. C. S.; Dean, F. M.; J ones, M. A.; Varma,
R. S. J . Chem. Soc., Perkin Trans. 1 1985, 799.
(25) Keenan, R. M.; Weinstock, J .; Franz, R. G.; Gaitanopoulos, D.
E.; Girad, G. R.; Gill, D. T.; Morgan, T. M.; Samanen, J . M.; Hempel,
J .; Eggleston, D. S.; Aiyar, N.; Grittin, E.; Ohlstein, E. H.; Stack, E.
J .; Weidley, E. F.; Edwards, R. J . Med. Chem. 1992, 35, 3870.
(26) Mart´ınez, A. G.; Alvarez, R. M.; Fraile, A. G. Synthesis 1986,
222.
(27) Sha, C.; Huang, S. Tetrahedron Lett. 1995, 36, 6927.
(28) Farnum, D. G.; Mostashari, A.; Hagedorn, A. A., III. J . Org.
Chem. 1971, 36, 698.
(20) Zenner, J . M. Ph.D. Dissertation, Iowa State University, 1996.
(29) Gemal, A. L.; Luche, J . L. J . Org. Chem. 1979, 44, 4187.

Palladium-Catalyzed Annulation of Internal Alkynes
J . Org. Chem., Vol. 63, No. 6, 1998 2007
Sch em e 1
H), 7.15 (m, 2 H), 7.34 (m, 3 H); 13C NMR (CDCl3) δ 18.8, 31.5,
34.7, 73.7, 105.5, 127.4, 127.5, 128.4, 145.8, 148.2; IR (CDCl3)
3380 (OH), 3020, 2937, 1409 cm-1;HRMS m/z 300.0006 (calcd
for C12H13IO, 300.0011).
diluted with ether, washed with satd NaHSO3 and water, dried
(MgSO4), filtered and concentrated. Chromatography (hex-
anes) gave a light yellow oil (0.39 g, 83%): 1H NMR (CDCl3) δ
2.68 (s, 3 H), 7.00-7.15 (m, 10 H); 13C NMR (CDCl3) δ 32.6,
100.2, 126.7, 127.2, 127.8, 128.0, 128.7, 130.1, 141.0, 144.6,
144.7; IR (CH2Cl2) 3027, 2922, 1492 cm-1; HRMS m/z 320.0059
(calcd for C15H13I, 320.0062).
2-Iod o-3-p h en ylin d en on e. 2-Iodo-3-phenylindenone was
prepared according to a literature procedure.30 An ICl solution
in CH2Cl2 (1 M, 1.62 mL, 1.62 mmol) was slowly added to a
solution of 3-phenyl-2-(trimethylsilyl)indenone9 in CH2Cl2 (1.5
mL) at 0 °C. The mixture was allowed to warm to room
temperature and stirred for 2 h. Then, the mixture was
quenched by adding excess ether, washed with Na2S2O3
solution, water, and brine, dried (MgSO4) and filtered. The
mixture was concentrated, followed by recrystallization from
CH2Cl2/MeOH. Orange crystals (0.4 g, 1.20 mmol, 89%) were
Gen er a l P r oced u r e for th e P a lla d iu m -Ca ta lyzed An -
n u la tion of Alk yn es by Vin ylic Iod id es or Tr ifla tes.
Pd(OAc)2 (2.8 mg, 0.0125 mmol), NaOAc (42 mg, 0.5 mmol),
n-Bu4NCl (208 mg, 0.75 mmol, procedure A) or LiCl (11 mg,
0.25 mmol, procedure B), vinylic iodide or triflate (0.25 mmol),
the alkyne (0.5 mmol, except 0.75 mmol for 4,4-dimethyl-2-
pentyne), and 5 mL of DMF were placed in a 4 dram vial,
which was heated in an oil bath at 100 °C for the period of
time indicated in Table 1. The reaction mixture was allowed
to cool, diluted with ether, washed with saturated NH4Cl, dried
over anhydrous MgSO4, and filtered. The solvent was evapo-
rated under reduced pressure and the product was isolated
by chromatography or preparative TLC.
1
obtained: mp 120-121 °C (CH2Cl2/MeOH); H NMR (CDCl3)
δ 7.09 (d, J ) 7.5 Hz, 1 H), 7.30 (m, 2 H), 7.6 (m, 6 H); 13C
NMR (CDCl3) δ 96.5, 121.1, 123.8, 128.1, 128.8, 130.2, 130.5,
132.8, 133.6, 146.5, 163.5, 191.6 (one sp2 C missing due to
overlap); IR (CDCl3) 3063, 3027, 1715 (CdO) cm-1;HRMS m/z
331.9705 (calcd for C15H9IO, 331.9698).
1,1-Dip h en yl-2-p r op en -2-yl Tr ifla te. 1,1-Diphenyl-2-pro-
pen-2-yl triflate was prepared according to a literature pro-
cedure.25 To a suspension of NaH (60% in mineral oil, 0.92 g,
22.9 mmol) in 30 mL of DMF at room temperature was added
dropwise 1,1-diphenylacetone (2.52 g, 12 mmol) in 10 mL of
DMF. After stirring for 2 h under N2, N-phenyltrifluo-
romethanesulfonimide (4.97 g, 13.8 mmol) was added in one
portion and the mixture was stirred overnight, diluted with
ether, washed with satd NH4Cl, water, and brine, dried
(MgSO4), and concentrated. Chromatography (hexanes) gave
a light yellow oil (1.4 g, 45%): 1H NMR (CDCl3) δ 2.24 (s, 3
H), 7.20-7.40 (m, 10 H); 13C NMR (CDCl3) δ 19.1, 118.1, 128.1,
128.2, 128.5, 129.6, 129.7, 135.6, 137.1, 138.3, 143.1 (one sp2
C missing due to overlap); IR (CH2Cl2) 3058, 2926, 1494, 1209
(SdO) cm-1; HRMS m/z 342.0538 (calcd for C16H13F3O3S,
342.0538).
The following compounds were prepared by the above
procedure.
9,10-Dip h en yl-1,2,3,4-tetr a h yd r op h en a n th r en e (entries
1 and 2, Table 1). Obtained as a white solid from the reaction
of compound 1 or 2 and diphenylacetylene using procedure A
after purification by column chromatography (hexanes): mp
190-192 °C (hexanes); 1H NMR (CDCl3) δ 1.80 (m, 2 H), 1.97
(m, 2 H), 2.57 (t, J ) 6.3 Hz, 2 H), 3.16 (t, J ) 6.3 Hz, 2 H),
7.00-7.65 (m, 13 H), 8.12 (d, J ) 8.4 Hz, 1 H); 13C NMR
(CDCl3) δ 23.0, 23.3, 26.6, 30.1, 122.7, 127.5, 125.0, 125.7,
126.2, 126.5, 127.4, 127.5, 130.2, 131.1, 131.2, 131.5, 131.8,
133.2, 136.7, 139.7, 139.8, 140.8; IR (CH2Cl2) 3054, 1491 cm-1
;
HRMS m/z 334.1719 (calcd for C26H22, 334.1721).
9-t er t -B u t y l-10-p h e n y l-1,2,3,4-t e t r a h y d r o p h e n a n -
th r en e (entries 3 and 4, Table 1). Obtained as a white solid
from the reaction of compound 1 or 2 and 3,3-dimethyl-1-
phenyl-1-butyne using procedure A after purification by
column chromatography (hexanes): mp 150-152 °C (hexanes);
1H NMR (CDCl3) δ 1.37 (s, 9 H), 1.61 (m, 2 H), 1.84 (m, 2 H),
2.17 (t, J ) 5.7 Hz, 2 H), 3.14 (t, J ) 6.0 Hz, 2 H), 7.18-7.48
(m, 7 H), 8.06 (d, J ) 8.1 Hz, 1 H), 8.53 (d, J ) 8.4 Hz, 1 H);
13C NMR (CDCl3) δ 22.8, 23.6, 27.1, 30.6, 35.3, 38.3, 122.8,
123.3, 124.6, 126.4, 127.3, 128.9, 130.4, 130.9, 131.0, 133.4,
2-Iod o-1,1-d ip h en yl-1-p r op en e. 2-Iodo-1,1-diphenyl-1-
propene was prepared according to a literature procedure.26
1,1-Diphenyl-2-propen-2-yl triflate (0.5 g, 1.5 mmol), MgI2 (1.2
g, 4.4 mmol), and Et3N (0.4 mL, 2.6 mmol) were placed in 20
mL of cyclohexane. The solution was refluxed at 95 °C for 10
h. After the reaction mixture was allowed to cool, it was
(30) Miller, R. B.; McGarvey, G. Synth. Commun. 1978, 8, 291.

2008 J . Org. Chem., Vol. 63, No. 6, 1998
Larock and Tian
134.1, 139.7, 140.6, 143.9; IR (CH2Cl2) 3074, 1429 cm-1;HRMS
m/z 314.2042 (calcd for C24H26, 314.2034).
NMR (CDCl3) δ 22.7, 23.3, 27.1, 29.7, 30.3, 63.32, 110.5, 122.8,
124.5, 125.4, 126.0, 127.5, 127.6, 128.2, 129.4, 132.6, 132.9,
133.8, 133.9, 138.9, 143.7; IR (CH2Cl2) 3054, 1599, 1191 (C-
O) cm-1; HRMS m/z 344.1778 (calcd for C24H24O2, 344.1776).
1-H yd r oxy-9,10-d ip h en yl-1,2,3,4-t et r a h yd r op h en a n -
th r en e (entry 20, Table 1). Obtained as a white solid in 51%
yield from the reaction of 2-iodo-3-phenylcyclohex-2-enol and
diphenylacetylene using procedure B after purification by
column chromatography (5:1 hexanes/ethyl acetate): mp 178-
9-(1-Hyd r oxy-1-m eth yleth yl)-10-p h en yl-1,2,3,4-tetr a h y-
d r op h en a n th r en e (entries 5 and 6, Table 1). Obtained as a
white solid from the reaction of compound 1 or 2 and 2-methyl-
4-phenyl-3-butyn-2-ol using procedure A after purification by
column chromatography (hexanes): mp 154-156 °C (hexanes);
1H NMR (CDCl3) δ 1.63 (s, 6 H), 1.66 (m, 2 H), 1.86 (m, 2 H),
2.19 (t, J ) 6.0 Hz, 2 H), 3.16 (t, J ) 5.7 Hz, 2 H), 7.18-7.52
(m, 7 H), 8.06 (d, J ) 8.1 Hz, 1 H), 8.75 (d, J ) 9.3 Hz, 1 H);
13C NMR (CDCl3) d 22.8, 23.4, 27.1, 30.4, 34.0, 76.0, 123.14,
123.8, 125.1, 126.7, 127.9, 128.8, 129.8, 131.6, 133.4, 133.7,
138.2, 139.3, 143.3 (one sp2 C missing due to overlap); IR
(CH2Cl2) 3589 (OH), 3054, 1422 cm-1; HRMS m/z 316.1826
(calcd for C23H23O, 316.1827).
9-t er t -B u t y l-10-m e t h y l-1,2,3,4-t e t r a h y d r o p h e n a n -
th r en e (entries 7 and 8, Table 1). Obtained as a white solid
from the reaction of compound 1 or 2 and 4,4-dimethyl-2-
pentyne using procedure A after purification by column
chromatography (hexanes): mp 84-86 °C (hexanes); 1H NMR
(CDCl3) δ 1.70 (s, 9 H), 2.43 (s, 3 H), 1.90 (m, 4 H), 2.75 (t, J
) 6.0 Hz, 2 H), 3.10 (t, J ) 6.0 Hz, 2 H), 7.33 (m, 2 H), 7.95
(dd, J ) 3.0, 9.0 Hz, 1 H), 8.31 (dd, J ) 3.0, 9.0 Hz, 1 H); 13C
NMR (CDCl3) δ 21.0, 22.9, 23.6, 26.4, 28.2, 34.2, 38.4, 121.9,
122.9, 123.6, 126.9, 129.3, 131.5, 131.9, 134.2, 135.0, 142.2;
IR (CH2Cl2) 3051, 1506 cm-1; HRMS m/z 252.1882 (calcd for
1
180 °C (CH2Cl2/MeOH); H NMR (CDCl3) δ 1.72 (dd, J ) 0.6,
3.6 Hz, 1 H), 1.87 (m, 1 H), 2.04 (m, 2 H), 2.21 (m, 1H), 3.10
(m, 1 H), 3.50 (m, 1 H), 4.81 (m, 1 H), 7.00 (m, 1 H), 7.11-
7.25 (m, 9 H), 7.39 (m, 1 H), 7.48-7.56 (m, 2 H), 8.14 (d, J )
8.4 Hz, 1 H); 13C NMR (CDCl3) δ 17.0, 26.3, 30.6, 64.5, 123.4,
126.1, 126.4, 126.7, 127.4, 127.5, 127.6, 127.7, 127.8, 130.3,
130.8, 131.1, 131.2, 132.2, 132.6, 133.8, 138.1, 139.3, 139.4,
139.7; IR (CDCl3) 3418 (OH), 3069, 2935, 1491 cm-1; HRMS
m/z 350.1671 (calcd for C26H22O, 350.1670).
5,6-Dip h en yl-7H-ben zo[c]flu or en -7-on e (entry 21, Table
1). Obtained as an orange solid in 54% yield from the reaction
of
2-iodo-3-phenylindenone
and
diphen-
ylacetylene using procedure B after purification by column
chromatography (10:1 hexanes/ethyl acetate): mp 238-240 °C
1
(CH2Cl2/MeOH); H NMR (CDCl3) δ 7.11 (m, 4 H), 7.19-7.33
(m, 7 H), 7.46-7.67 (m, 5 H), 8.15 (d, J ) 7.5 Hz, 1 H), 8.65
(d, J ) 7.8 Hz, 1 H); 13C NMR (CDCl3) δ 123.4, 123.9, 124.8,
126.7, 127.0, 127.2, 127.4, 127.7, 128.5, 128.6, 128.7, 128.8,
128.9, 129.9, 131.1, 134.3, 134.7, 136.2, 136.8, 137.2, 138.1,
141.3, 143.0, 144.0, 193.9; IR (CDCl3) 3073, 3022, 1710 (CdO),
1602 cm-1; HRMS m/z 382.1360 (calcd for C29H18O, 382.1358).
5,6-Dip h en yl-7H-ben zo[c]xa n th en -7-on e (entry 22, Table
1). Obtained as a red solid in 25% yield from the reaction of
2-iodoflavone and diphenylacetylene using procedure B after
purification by column chromatography (10:1 hexanes/ethyl
C
19H24, 252.1878).
10-E t h yl-9-(1-h yd r oxycycloh exyl)-1,2,3,4-t et r a h yd r o-
p h en a n th r en e (entries 9 and 10, Table 1). Obtained as a
white solid from the reaction of compound 1 or 2 and 1-(1-
butynyl)cyclohexanol using procedure A after purification by
column chromatography (hexanes): mp 88-90 °C (hexanes);
1H NMR (CDCl3) δ 1.27 (t, J ) 4.0 Hz, 3 H), 1.50-1.98 (m, 14
H), 2.75 (dt, J ) 4.5, 10 Hz, 2 H), 2.92 (t, J ) 6.0 Hz, 2 H),
3.13 (t, J ) 6.0 Hz, 2 H), 3.23 (br s, 1 H), 7.29-7.40 (m, 2 H),
7.96 (dd, J ) 3.0, 9.0 Hz, 1 H), 8.56 (d, J ) 9.0 Hz, 1 H); 13C
NMR (CDCl3) δ 16.4, 22.3, 22.9, 23.6, 24.2, 25.1, 27.0, 27.1,
38.3, 77.4, 122.5, 122.8, 123.9, 127.3, 129.9, 131.2, 132.2, 135.0,
139.9, 140.0; IR (CH2Cl2) 3587 (OH), 3072, 1449 cm-1; HRMS
m/z 308.2146 (calcd for C22H28O, 308.2140).
10-P h en yl-9-(t r iet h ylsilyl)-1,2,3,4-t et r a h yd r op h en a n -
th r en e (entries 11 and 12, Table 1). Obtained as a white solid
from the reaction of compound 1 or 2 and 1-phenyl-2-(trieth-
ylsilyl)acetylene using procedure A or B after purification by
column chromatography (hexanes): mp 124-125 °C (hexanes);
1H NMR (CDCl3) δ 0.52 (q, J ) 7.5 Hz, 6 H), 0.80 (t, J ) 7.5
Hz, 9 H), 1.68 (m, 2 H), 1.89 (m, 2 H), 2.27 (t, J ) 6.0 Hz, 2
H), 3.20 (t, J ) 6.0 Hz, 2 H), 7.19-7.22 (m, 2 H), 7.37 (m, 3
H), 7.48 (m, 2 H), 8.07 (dd, J ) 3.0, 7.5 Hz, 1 H), 8.30 (dd, J
) 3.0, 7.5 Hz, 1 H); 13C NMR (CDCl3) δ 5.6, 8.3, 22.8, 23.3,
26.9, 30.1, 123.3, 123.9, 124.9, 126.9, 127.6, 128.7, 130.6, 130.7,
131.9, 133.1, 133.4, 135.9, 143.7, 150.1; IR (CH2Cl2) 3055, 1456
cm-1; HRMS m/z 372.2278 (calcd for C26H32Si, 372.2273).
10-P h en yl-9-(tr im eth ylsilyl)-1,2,3,4-tetr a h yd r op h en a n -
th r en e (entries 13-15, Table 1). Obtained as a white solid
from the reaction of compound 1 or 2 and 1-phenyl-2-(trim-
ethylsilyl)acetylene using procedure A or B after purification
by column chromatography (hexanes): mp 144-145 °C (hex-
anes); 1H NMR (CDCl3) δ 0.04 (s, 9 H), 1.68 (m, 2 H), 1.90 (m,
2 H), 2.33 (t, J ) 6.0 Hz, 2 H), 3.20 (t, J ) 6.0 Hz, 2 H), 7.22
(m, 2 H), 7.38 (m, 3 H), 7.49 (m, 2 H), 8.08 (dd, J ) 3.0, 9.0
Hz, 1 H), 8.25 (dd, J ) 3.0, 9.0 Hz, 1 H); 13C NMR (CDCl3) δ
2.8, 22.8, 23.3, 26.9, 30.1, 123.4, 124.2, 125.1, 127.0, 127.9,
129.3, 130.5, 132.1, 133.1, 133.2, 133.5, 135.4, 143.6, 148.8;
IR (CH2Cl2) 3054, 1457 cm-1; HRMS m/z 330.1806 (calcd for
1
acetate): mp 190-192 °C (hexanes); H NMR (CDCl3) δ 6.64
(d, J ) 8.4 Hz, 1 H), 7.15 (t, J ) 7.5 Hz, 1 H), 7.21-7.37 (m,
13 H), 7.49 (t, J ) 8.4 Hz, 1 H), 7.77 (d, J ) 7.8 Hz, 1 H), 9.34
(d, J ) 7.5 Hz, 1 H); 13C NMR (CDCl3) δ 112.5, 121.4, 121.9,
123.3, 124.5, 126.7, 127.0, 127.4, 127.9, 128.1, 129.4, 129.5,
130.3, 130.9, 133.8, 134.2, 136.6, 137.0, 137.8, 143.0, 146.4,
148.5, 164.4, 184.8 (one sp2 C missing due to overlap); IR
(CDCl3) 3102, 3057, 1685 (CdO), 1599 cm-1; HRMS m/z
398.1310 (calcd for C29H18O2, 398.1307).
3-Ben zoyl-2-(2-h yd r oxyp h en yl)-4,5-d ip h en ylfu r a n (en-
try 22, Table 1). Obtained as an orange solid in 61% yield
from the reaction of 3-iodoflavone and diphenylacetylene using
procedure B after purification by column chromatography (10:1
1
hexanes/ethyl acetate): mp 184-186 °C (hexanes); H NMR
(CD2Cl2) δ 7.0 (m, 2 H), 7.17-7.48 (m, 12 H), 7.52 (m, 3 H),
7.70 (m, 2 H), 8.24 (s, 1 H); 13C NMR (CDCl3) δ 118.1, 118.6,
121.0, 123.7, 125.4, 126.5, 127.9, 128.3, 128.6, 128.8, 128.9,
130.1, 130.2, 130.3, 130.7, 131.6, 132.4, 133.6, 137.5, 149.4,
151.1, 154.8, 195.2; IR (CDCl3) 3305 (OH), 3060, 3031, 1656
(CdO) cm-1; HRMS m/z 416.1411 (calcd for C29H20O3, 416.1412).
5-ter t-Bu tyl-6-m eth yl-7H-ben zo[c]xa n th en -7-on e (entry
23, Table 1). Obtained as an orange solid in 10% yield from
the reaction of 3-iodoflavone and 4,4-dimethyl-2-pentyne using
procedure B after purification by column chromatography (10:1
1
hexanes/ethyl acetate): mp 125-127 °C (hexanes); H NMR
(CDCl3) δ 1.65 (s, 9 H), 2.83 (s, 3 H), 7.40 (t, J ) 8.5 Hz, 1 H),
7.62 (m, 2 H), 7.72 (m, 2 H), 8.05 (d, J ) 8.5 Hz, 1 H), 8.20
(dd, J ) 1.5, 7.8 Hz, 1 H), 8.61 (dd, J ) 1.5, 8.1 Hz, 1 H); 13C
NMR (CDCl3) δ 19.7, 32.0, 39.2, 103.3, 117.0, 122.7, 123.2,
123.9, 124.1, 124.9, 125.9, 126.4, 129.6, 130.5, 133.4, 136.4,
145.2, 152.6, 154.2, 180.2; IR (CDCl3) 3106, 3060, 1685 (CdO),
1610 cm-1; HRMS m/z 316.1460 (calcd for C22H20O2, 316.1463).
2-ter t-Bu tyl-4-ben zoyl-5-(2-h yd r oxyp h en yl)-1-m eth yl-
fu r a n (entry 23, Table 1). Obtained as an orange solid in 69%
yield from the reaction of 3-iodoflavone and 4,4-dimethyl-2-
pentyne using procedure B after purification by column
chromatography (10:1 hexanes/ethyl acetate): mp 170-172 °C
(hexanes); 1H NMR (CD2Cl2) δ 1.42 (s, 9 H), 1.97 (s, 3 H), 6.76
(dt, J ) 0.9, 7.5 Hz, 1 H), 6.93 (dd, J ) 1.2, 8.7 Hz, 1 H), 7.16
(m, 2 H), 7.37 (t, J ) 7.5 Hz, 2 H), 7.48 (m, 1 H), 7.80 (d, J )
6.0 Hz, 2 H), 8.10 (s, 1 H); 13C NMR (CDCl3) δ 10.7, 29.4, 34.0,
C
23H26Si, 330.1804).
9-(2-Met h yl-2-(1,3-d ioxola n yl))-10-p h en yl-1,2,3,4-t et -
r a h yd r op h en a n th r en e (entries 16 and 17, Table 1). Ob-
tained as a white solid from the reaction of compound 1 or 2
and 2-(2-phenyl-1-ethynyl)-2-methyl-1,3-dioxolane using pro-
cedure A after purification by column chromatography (hex-
anes): mp 175-176 °C (hexanes); 1H NMR (CDCl3) δ 1.67 (m,
2 H), 1.86 (m, 2 H), 1.96 (s, 3 H), 2.22 (t, J ) 6.0 Hz, 2 H), 3.17
(t, J ) 6.0 Hz, 2 H), 3.53 (m, 2 H), 3.70 (m, 2 H), 7.16 (m, 2 H),
7.38 (m, 3 H), 7.51 (m, 2 H), 8.05 (m, 1 H), 8.82 (m, 1 H); 13C

Palladium-Catalyzed Annulation of Internal Alkynes
J . Org. Chem., Vol. 63, No. 6, 1998 2009
113.7, 117.6, 118.0, 120.3, 124.6, 128.4, 129.9, 130.0, 130.5,
133.4, 137.8, 148.7, 154.1, 157.8, 195.2; IR (CDCl3) 3340 (OH),
3060, 2970, 1652 cm-1; HRMS m/z 334.1570 (calcd for C22H22O3,
334.1569).
reaction of 2-iodo-1,1-diphenylethylene and 1-phenyl-2-(trim-
ethylsilyl)acetylene using procedure B after purification by
column chromatography (hexanes): mp 146-148 °C (hexanes);
1H NMR (CDCl3) δ 0.16 (s, 9 H), 7.36-7.53 (m, 13 H), 7.97 (d,
J ) 8.7 Hz, 1 H), 8.30 (d, J ) 8.7 Hz, 1 H); 13C NMR (CDCl3)
δ 2.8, 125.1, 125.2, 126.8, 127.3, 127.4, 128.0, 128.3, 129.3,
129.6, 130.0, 130.1, 130.6, 134.9, 138.4, 140.5, 140.8, 145.5,
148.3; IR (CDCl3) 3058, 2847, 1486 cm-1; HRMS m/z 352.1647
(calcd for C25H24Si, 352.1647).
1,2,4-Tr ip h en yln a p h th a len e (entries 24 and 25, Table 1).
Obtained as a white solid in 49% yield from the reaction of
2-iodo-1,1-diphenylethylene and diphenylacetylene using pro-
cedure B after purification by column chromatography (hex-
1
anes): mp 159-161 °C (hexanes); H NMR (CDCl3) δ 7.16-
7.21 (m, 5 H), 7.25-7.34 (m, 5 H), 7.43-7.63 (m, 8 H), 7.77
(m, 1 H), 8.01 (m, 1 H); 13C NMR (CDCl3) δ 125.8, 126.0, 126.1,
126.3, 126.8, 127.2, 127.4, 127.6, 127.9, 128.4, 129.4, 130.1,
130.2, 131.0, 131.6, 133.1, 137.2, 137.9, 139.1, 139.8, 140.7,
141.9; IR (CDCl3) 3059, 3026, 1600 cm-1; HRMS m/z 356.1560
(calcd for C28H20, 356.1565).
1-ter t-Bu tyl-2,4-d ip h en yln a p h th a len e a n d 2-ter t-Bu tyl-
1,4-d ip h en yln a p h th a len e (entry 26, Table 1). Obtained as
a 3:1 mixture of regioisomers in 62% yield from the reaction
of 2-iodo-1,1-diphenylethylene and 3,3-dimethyl-1-phenyl-1-
butyne after purification by column chromatography. The
mixture was partially separated through preparative TLC and
2-Meth yl-1,3,4-tr ip h en yln a p h th a len e (entry 30, Table 1).
Obtained as a white solid in 65% yield from the reaction of
2-iodo-1,1-diphenylpropene
and
diphen-
ylacetylene using procedure B after purification by column
chromatography (hexanes): mp 160-163 °C (hexanes); 1H
NMR (CDCl3) δ 2.56 (s, 3 H), 6.78-6.86 (m, 5 H), 7.05-7.25
(m, 10 H), 7.43 (t, J ) 8.1 Hz, 1 H), 7.62 (m, 2 H), 8.19 (d, J )
8.5 Hz, 1H); 13C NMR (CDCl3) δ 17.2, 124.5, 125.2, 125.8, 126.0,
126.3, 127.3, 127.4, 127.6, 130.6, 131.2, 131.3, 131.4, 132.0,
132.1, 136.9, 139.0, 139.3, 139.7, 140.8, 141.4 (two sp2 C’s
missing due to overlap); IR (CDCl3) 3058, 2923, 1602 cm-1
;
HRMS m/z 370.1720 (calcd for C29H22, 370.1722).
both
pure
isomers
were
isolated.
1-ter t-Bu tyl-3-m eth yl-2,4-d ip h en yln a p h th a len e (entry
31, Table 1). Obtained as a white solid in 46% yield from the
reaction of 2-iodo-1,1-diphenylethylene and 3,3-dimethyl-1-
phenyl-1-butyne using procedure B after purification by
column chromatography (hexanes): mp 171-173 °C (hexanes);
1H NMR (CDCl3) δ 1.41 (s, 9 H), 2.34 (s, 3 H), 6.81-7.08 (m,
10 H), 7.52 (m, 2 H), 8.14 (m, 1 H), 8.63 (m, 1 H); 13C NMR
(CDCl3) δ 17.4, 35.2, 38.4, 123.5, 124.8, 125.2, 125.5, 125.6,
126.2, 127.1, 129.0, 129.9, 130.0, 131.8, 132.2, 133.2, 139.1,
1-tert-Butyl-2,4-diphenylnaphthalene: mp 139-140 °C (hex-
1
anes); H NMR (CDCl3) δ 1.26 (s, 9 H), 7.15-7.38 (m, 5 H),
7.45-7.60 (m, 8 H), 7.71 (s, 1 H), 7.89 (d, J ) 8.1 Hz, 1 H); 13
C
NMR (CDCl3) δ 33.2, 37.2, 125.1, 125.4, 127.0, 127.1, 127.2,
127.3, 127.6, 128.3, 129.8, 130.3, 131.7, 134.9, 137.0, 139.3,
141.4, 141.8, 144.2 (one sp2 C missing due to overlap); IR
(CDCl3) 3074, 2962, 1492 cm-1;HRMS m/z 336.1887 (calcd for
C
26H24, 336.1878). 2-tert-Butyl-1,4-diphenylnaphthalene: mp
1
138-140 °C (hexanes); H NMR (CDCl3) δ 1.50 (s, 9 H), 7.15
(s, 1 H), 7.33-7.54 (m, 12 H), 7.96 (m, 1 H), 8.63 (d, J ) 8.7
Hz, 1 H); 13C NMR (CDCl3) δ 35.0, 38.2, 123.9, 124.6, 126.4,
127.1, 127.2, 127.5, 128.2, 128.4, 129.6, 130.2, 132.1, 132.3,
133.4, 137.5, 139.1, 140.6, 142.4, 147.1; IR (CH2Cl2) 3069, 2926,
1596 cm-1; HRMS m/z 336.1880 (calcd for C26H24, 336.1878).
1-ter t-Bu tyl-2-m eth yl-4-p h en yln a p h th a len e (entry 28,
Table 1). Obtained as a white solid in 52% yield from the
reaction of 2-iodo-1,1-diphenylethylene and 4,4-dimethyl-2-
pentyne using procedure B after purification by column
chromatography (hexanes): mp 139-140 °C (hexanes); 1H
NMR (CDCl3) δ 1.56 (s, 9 H), 2.93 (s, 3 H), 7.36-7.56 (m, 8
H), 7.86 (d, J ) 8.7 Hz, 1 H), 8.18 (d, J ) 8.7 Hz, 1 H); 13C
NMR (CDCl3) δ 18.2, 31.9, 36.0, 124.2, 125.0, 125.7, 126.2,
126.3, 127.0, 128.2, 130.0, 130.3, 131.1, 134.4, 137.8, 141.6,
144.4; IR (CDCl3) 3058, 2956, 1591 cm-1; HRMS m/z 274.1719
(calcd for C21H22, 274.1722).
140.8, 141.1, 142.2, 143.9; IR (CDCl3) 3064, 2927, 1599 cm-1
;
HRMS m/z 350.2032 (calcd for C27H26, 350.2034).
Ack n ow led gm en t. We thank the donors of the
Petroleum Research Fund, administered by the Ameri-
can Chemical Society, for support of this research.
Thanks also go to J ohnson Matthey, Inc. and Kawaken
Fine Chemicals Co., Ltd. for donating Pd(OAc)2.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra for all compounds in Table 1 (42 pages). This material
is contained in libraries on microfiche, immediately follows this
article in the microfilm version of the journal, and can be
ordered from the ACS; see any current masthead page for
ordering information.
1-(Tr im eth ylsilyl)-2,4-d ip h en yln a p h th a len e (entry 29,
Table 1). Obtained as a white solid in 19% yield from the
J O972154B