Generation of o-quinodimethanes via the electrocyclic reaction of (4Z)-1,2,4,6,7-octapentaenes derived from the organoborate complexes and their subsequent reactions

Article abstract of DOI:10.1016/S0022-328X(99)00056-X

Treatment of allenyldicyclohexylborane (20) with 1-lithio-3,4-pentadien-1-yne 21 produced the organoborate complex 22, which on further treatment with trimethyltin chloride furnished the enediallene 23 in situ. The subsequent electrocyclic reaction then g

Full text of DOI:10.1016/S0022-328X(99)00056-X

Journal of Organometallic Chemistry 581 (1999) 108–115
Generation of o-quinodimethanes via the electrocyclic reaction of
(4Z)-1,2,4,6,7-octapentaenes derived from the organoborate
complexes and their subsequent reactions
Quan Zhang, Kung K. Wang *
Department of Chemistry, West Virginia Uni6ersity, Morgantown, WV 26506, USA
Received 30 June 1998; received in revised form 30 November 1998
Abstract
Treatment of allenyldicyclohexylborane (20) with 1-lithio-3,4-pentadien-1-yne 21 produced the organoborate complex 22, which
on further treatment with trimethyltin chloride furnished the enediallene 23 in situ. The subsequent electrocyclic reaction then
generated the o-quinodimethane 24, which underwent a [1,5]-sigmatropic hydrogen shift to afford 25. Oxidative work-up followed
by protonation gave the phenol 26. The presence of a boron group and a tin group in 25 also provides handles to allow their
transformations to an allyl substituent and an iodo substituent in 27. Attempts to capture the o-quinodimethane in 32 with the
carbon–carbon double bond intramolecularly afforded the tricyclic phenol 34 in low yield (6%). By using the combination of the
organoborane 36 and 1-lithio-1,2-heptadiene (37) to form the organoborate complex 38, the o-quinodimethane 40 could also be
generated in situ, leading to the phenol 42 and the styrene 43. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Boron; o-Quinodimethanes; Electrocyclization; (Z)-1,2,4,6,7-Octapentaenes; Organoborates
(3.3%) (see Scheme 2) [4a]. Presumably, the reaction
proceeds through an initial 1,4-elimination to form the
o-quinodimethanes 6a as the major isomer and 6b as
the minor isomer followed by a [1,5]-sigmatropic hydro-
gen shift.
1. Introduction
o-Quinodimethanes are reactive intermediates and
their chemical reactivities have been exploited for a
variety of synthetic applications [1]. The intramolecular
Diels–Alder reactions provide efficient pathways to
many polycyclic systems. For example, treatment of 1
with tetrabutylammonium fluoride (TBAF) in refluxing
acetonitrile induced a 1,4-elimination to form the o-
quinodimethane 3 having the E geometry, which then
underwent an intramolecular Diels–Alder reaction to
furnish 4 having the trans ring junction (Scheme 1) [2].
Alternatively, thermolysis of the sulfone 2 at 210°C to
promote extrusion of sulfur dioxide also gave 3 and
consequently 4 (trans:cis=5:1) in 65% yield [3].
In addition to the 1,4-elimination reactions of the
a,a%-disubstituted o-xylenes, such as those shown in
Schemes 1 and 2, many other synthetic routes to o-
quinodimethanes have been developed [1–8]. An inter-
esting but less studied route to o-quinodimethanes
involves the electrocyclic reaction of (4Z)-1,2,4,6,7-oc-
tapentaenes (enediallenes). The parent (Z)-1,2,4,6,7-oc-
tapentaene (9) was generated in situ by treatment of
(Z)-4-octene-1,7-diyne (8) with potassium tert-butoxide
(Scheme 3) [9]. The subsequent electrocyclic reaction
gave the parent o-quinodimethane 10, which then pro-
duced the spiro dimer 11 and the linear dimer 12.
Isomerization from 9 to 10 must be a very facile
process. The corresponding benzofused [10,11] and
naphthofused [10] analogues with a fused central car-
bon–carbon double bond isomerize rapidly to 2,3-
naphthoquinodimethane and 2,3-anthraquinodime-
thane, respectively, at ambient or subambient tempera-
For the a-substituted o-quinodimethanes having a
(Z)-allylic hydrogen, the [1,5]-sigmatropic hydrogen
shift is a facile process [4]. Specifically, treatment of the
sulfone 5 with TBAF produced both 7a (45%) and 7b
* Corresponding author. Tel.: +1-304-293-3068; fax: +1-304-293-
4904.
E-mail address: kwang@wvu.edu (K.K. Wang)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00056-X

Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
109
Scheme 3.
2. Results and discussion
Scheme 1.
Allenyldicyclohexylborane (20) was readily prepared
by treatment of chlorodicyclohexylborane (19) with al-
lenylmagnesium bromide (Scheme 5). Sequential treat-
ment of 20 with 1-lithio-3,4-pentadien-1-yne 21,
Me3SnCl, an alkaline H2O2 solution, and acetic acid
produced the phenol 26 in a single operation. Appar-
ently, trimethyltin chloride also promoted a stereoselec-
tive migration of the allenyl group in 22 to the adjacent
acetylenic carbon atom to afford the enediallene 23.
The electrocyclic reaction of 23 then generated the
o-quinodimethane 24, giving rise to 25 through a [1,5]-
sigmatropic hydrogen shift. Oxidative work-up fol-
lowed by protonation with acetic acid then gave 26 in
51% yield.
The presence of a dicyclohexylboryl group and a
trimethyltin group in 25 also affords opportunities for
other chemical transformations. Treatment of 25 with
n-butyllithium followed by CuBr·SMe2 and allyl bro-
mide transformed the dicyclohexylboryl substituent to
the allyl group, presumably via an organocopper inter-
tures. In addition, the electrocyclic reaction of (4Z)-
1,2,4,6-heptatetraenes to 5-methylene-1,3-cyclohexadi-
enes (o-isotoluenes) is known to be vary facile [12].
However, with the exception of the benzofused and the
naphthofused analogues, other o-quinodimethanes have
not been prepared via the electrocyclic reaction of
enediallenes.
We recently reported a facile synthesis of o-isotolue-
nes via the electrocyclic reaction of (4Z)-1,2,4,6-hep-
tatetraenes (Scheme 4) [12d]. Treatment of
alkenyldicyclohexylboranes 13 with 1-lithio-3,4-penta-
dien-1-ynes, derived from lithiation of the correspond-
ing 3,4-pentadien-1-ynes with n-butyllithium, followed
by trimethyltin chloride and acetic acid furnished the
o-isotoluenes 18. Presumably, the reaction proceeds
through the formation of the organoborate complexes
15 followed by the trimethyltin chloride-induced trans-
formation to form 16 with the dicyclohexylboryl group
and the trimethyltin group cis to each other [13]. The
electrocyclic reaction of 16 then produces 17 and subse-
quently, after protonation with acetic acid, the o-iso-
toluenes 18. We envisioned that the reaction sequence
outlined in Scheme 4 could be adopted for the synthesis
of enediallenes for subsequent conversion to o-
quinodimethanes by substitution of the alkenyldicyclo-
hexylboranes 13 with allenyldicyclohexylboranes.
Scheme 2.
Scheme 4.

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Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
chemical shift of the alkenyl hydrogen of the major
product at l 5.18 is 0.24 ppm upfield from that of the
minor product at l 5.42. It was reported previously that
1
the H-NMR chemical shift of the alkenyl hydrogen of
the Z isomer of 1-(1-ethyl-1-propenyl)-2-methylbenzene
at l 5.35 is 0.24 ppm upfield from that of the E isomer
at l 5.59 [4a]. The chemical shift correlation appears to
suggest that the Z isomer of 30 is the predominant
product. In any event, the E isomer is produced from
the conformer 29a, while the Z isomer is derived from
the conformer 29b.
The relative severity of the A(1,2) allylic strain in 29a
versus the A(1,3) allylic strain [14] in 29b determines the
ratio of the resulting E and Z isomers. The preferential
formation of the E isomer was reported previously in
the system leading to the formation of 1-(1-ethyl-1-
propenyl)-2-methylbenzene [4a].
It was possible to capture the o-quinodimethane in
32, derived from 20 and 31, with the carbon–carbon
double bond for the intramolecular Diels–Alder reac-
tion to afford 33, which on oxidative work-up and
protonation gave the tricyclic phenol 34 having pre-
dominantly the trans ring junction (trans:cis\10:1)
(Scheme 7). Unfortunately, the overall isolated yield of
34 is only 6%. A small amount of 4-[(1E)-1,6-heptadi-
enyl]-3-methylphenol (ca. 1%), presumably derived
from a [1,5]-sigmatropic hydrogen shift of the Z isomer
of 32, was also produced. The effect of the boron and
the tin substituents on the reactivity of the o-
quinodimethane in 32 for the intramolecular Diels–
Alder reaction remains to be determined.
Scheme 5.
mediate [13e–h]. Further treatment of the resulting
adduct with I2 replaced the trimethyltin group with an
iodo substituent [13e–h] to furnish 27 having a tetra-
substituted benzene ring.
By using 28 to form the organoborate complex with
20, the o-quinodimethane 29 was generated in situ
(Scheme 6). The subsequent [1,5]-sigmatropic hydrogen
shift then furnished 30 as a mixture of the E and the Z
isomers (isomer ratio=84:16) in 60% yield. Whether
the E isomer or the Z isomer was produced as the
predominant product has not been determined defini-
1
tively. However, it is worth noting that the H-NMR
Scheme 6.
Scheme 7.

Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
111
treatment of 5-butyl-3,4-nonadien-1-yne (35) with n-
butyllithium, B-methoxydicyclohexylborane, and
4/3BF3·OEt2 [15] generated 36 in situ (Scheme 8). Fur-
ther treatment of 36 with 1-lithio-1,2-heptadiene (37)
gave the requisite organoborate complex 38 for trans-
formation to the o-quinodimethane 40, leading to 41
and subsequently, after oxidative work-up and protona-
tion, to the phenol 42 (61% yield, isomer ratio=87:13).
Direct protonation of 41 with acetic acid furnished 43
in 57% yield.
By using the combination of 3,4,10-undecatrien-1-yne
(44) and 37 to form the organoborate complex 45, the
phenols 53 (20%), 54 (10%) and 55 (15%) were obtained
(Scheme 9). Apparently, 53 was produced via the in-
tramolecular Diels–Alder reaction of 47 to form 50,
whereas 54 and 55 were produced via the [1,5]-sigmat-
ropic hydrogen shift of 48 and 49 to form 51 and 52,
respectively.
It is worth noting that the enediallene 46 is most
likely a 1:1 mixture of the two diastereomers 46a and
46b. If the disrotatory motion of the six p-electron
system is also required for the thermally induced elec-
trocyclic reactions of 46a and 46b, then 46a will be the
precursor of 47 (Eq. (1)) whereas 46b will be the
precursor of both 48 and 49 (Eq. (2)) [16].
Scheme 8.
An alternative pathway to the organoborate com-
plexes for the subsequent formation of o-
quinodimethanes has also been developed. Sequential
(1)
Scheme 9.

112
Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
trimethyltin chloride (1.0 M solution in THF), n-butyl-
lithium (2.5 M solution in hexanes), CuBr·SMe2,
BF3·OEt2, propargyl bromide (80 wt.% solution in
toluene) were purchased from Aldrich Chemical Co.,
and were used as received. Allenylmagnesium bromide
was prepared according to the reported procedure [18].
B-Methoxydicyclohexylborane was prepared by treat-
ment of dicyclohexylborane with methanol [19]. 5,5-
(Pentamethylene)-3,4-pentadienl-1-yne and 5-butyl-3,4-
nonadienl-1-yne (35) were prepared as reported previ-
ously [12d]. Similarly, 3,4,10-undecatrien-1-yne (44) was
synthesized in 52% overall yield from cross-coupling of
1,2,8-nonatriene [20] with 1-iodo-2-(trimethylsi-
lyl)ethyne (69%) followed by desilylation (75%). 1,2-
Heptadiene was prepared as reported previously [21].
1H (270 MHz) and 13C (67.9 MHz) -NMR spectra were
recorded in CDCl3 using CHCl3 (1H l 7.25) and CDCl3
(13C l 77.00) as internal standards.
Scheme 10.
(2)
The fact that substantial amounts of 54 and 55 (com-
bined yield=25%) were produced appears to suggest
that the stereoelectronic requirement for the electro-
cyclic reaction dictates the transformation of 46b to the
sterically less favorable 48 and 49 with one of the
exocyclic double bonds having the Z geometry. Other-
wise, one would expect a preferential formation of 47
with both of the exocyclic double bonds having the E
geometry. However, the possibility of producing 47–49
from 46 via a biradical pathway without the require-
ment of an initial disrotatory motion (Scheme 10) could
not be ruled out. A one-step intramolecular ene reac-
tion of 46 could also produce 51 and 52 directly [17].
4.1. Allenyldicyclohexylborane (20)
The procedure for the synthesis of B-allenyl-9-
borabicyclo[3.3.l]nonane [22] was adopted for the
preparation of 20. Allenylmagnesium bromide was pre-
pared as described previously [18]. To 0.48 g (20.0
mmol) of magnesium turnings under a nitrogen atmo-
sphere were added 20 ml of anhydrous diethyl ether
and 2 drops of 1,2-dibromoethane. After 10 min, 0.010
g of mercury(II) chloride was added followed by drop-
wise addition of 1.34 ml of a 80 wt.% solution of
propargyl bromide (12.0 mmol) in toluene over 20 min.
The reaction flask was immersed in a cold water bath
when the Grignard reaction became too vigorous. The
reaction mixture was stirred at r.t. for 1 h. The resulting
mixture was then transferred via cannula to a flask
containing 10.0 ml of a 1.0 M solution of chlorodicy-
clohexylborane (10.0 mmol) in hexanes and 20 ml of
diethyl ether maintained at −78°C. After 30 min, the
mixture was allowed to warm to r.t. After 1 h, stirring
was discontinued to allow magnesium salt to settle. The
solution was transferred via cannula to centrifuge tubes
for centrifugation. The clear supernatant liquid was
transferred via cannula to a flask and was concentrated
in vacuo. The residue was distilled in vacuo (b.p. 98°C,
0.02 Torr) to give 1.372 g (6.35 mmol, 64%) of 20 as a
3. Conclusions
A new synthetic pathway to (4Z)-1,2,4,6,7-octapen-
taenes as precursors of o-quinodimethanes has been
developed. The ability to generate enediallenes with
high geometric purity via the corresponding organobo-
rate complexes in a single operation is an especially
attractive feature. The process is very flexible, allowing
easy assembly of various readily available fragments to
produce the requisite organoborate complexes. The
presence of the boron and the tin substituents in the
cyclized adducts also affords opportunities to introduce
other functional groups onto the benzene ring.
1
colorless liquid: H l 5.56 (1 H, t, J=6.5 Hz), 4.56 (2
H, d, J=6.7 Hz), 1.76–1.62 (6 H, m), 1.53–1.43 (4 H,
m), 1.28–1.14 (12 H, m); 13C l 220.15, 87.5 (br), 68.54,
34.5 (br), 27.49, 27.43, 27.01.
4. Experimental
All reactions were conducted in oven-dried (120°C)
glassware under a nitrogen atmosphere. Tetrahydro-
furan (THF) and diethyl ether (Et2O) were distilled
from benzophenone ketyl prior to use. Chlorodicyclo-
4.2. 4-(1-Cyclohexenyl)-3-methylphenol (26)
The following procedure for the preparation of 26 is
representative. To 0.264 g (2.00 mmol) of 5,5-(pen-
tamethylene)-3,4-pentadien-1-yne in 20 ml of THF at
hexylborane (19, 1.0
M
solution in hexanes),

Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
113
−78°C was added 1.25 ml (2.00 mmol) of a 1.6 M
solution of n-butyllithium in hexanes. After 30 min at
−78°C, 0.475 g (2.20 mmol) of 20 in 10.0 ml of THF
was introduced via cannula. After 30 min, the mixture
was allowed to warm to r.t. After an additional 2 h, the
mixture was cooled to 0°C, and 2.0 ml of a 1.0 M
solution of trimethyltin chloride (2.0 mmol) in THF
were added with a syringe. After 15 h of stirring at r.t.,
the mixture was transferred via cannula to a flask
containing a mixture of 2.0 ml of a 30% H2O2 solution
and 2 ml a 6 N NaOH solution in 15 ml of methanol at
0°C. The reaction mixture was heated at 50°C for 1 h
before it was allowed to cool to rt. Glacial acetic acid
(2.0 ml) was added, and the mixture was heated at 50°C
for 2 h. The organic layer was separated, and the
aqueous layer was extracted with pentane (3×20 ml).
The combined organic layers were washed with water,
dried over MgSO4, and concentrated. The residue was
purified by column chromatography (silica gel/20%
Et2O in hexanes) to furnish 0.192 g (1.02 mmol, 51%)
of 26 as a light yellow liquid: IR (neat) 3331, 1605,
dq, J=10 and 1.6 Hz), 5.12 (1 H, dq, J=17 and 1.8
Hz), 3.44 (2 H, dt, J=6.5 and 1.5 Hz), 2.20 (3 H, s),
2.19–2.11 (4 H, m), 1.79–1.62 (4 H, m); 13C l 144.70,
140.34, 138.73, 137.31, 136.01, 135.51, 131.04, 126.48,
116.44, 96.75, 44.42, 29.89, 25.33, 22.96, 22.06, 19.36;
MS (m/z) 338 (M+), 297, 211, 170, 169. Anal. Calc. for
C16H19I: C, 56.82; H, 5.66. Found: C, 57.04; H, 5.68.
4.4. 4-(1-Butyl-1-pentenyl)-3-methylphenol (30)
The same procedure was repeated as described for 26
except that 0.352 g (2.00 mmol) of 5-butyl-3,4-nona-
dien-1-yne (35) was treated with 0.80 ml (2.00 mmol) of
a 2.5 M solution of n-butyllithium in hexanes to pro-
duce 28 followed by 0.561 g (2.6 mmol) of 20. The
phenol 30 (0.279 g, 1.20 mmol, 60%) was isolated as a
light yellow liquid: IR (neat) 3353, 1607, 1581, 1235,
1
860, 816 cm−1; H l 6.89 (1 H, d, J=8.1 Hz), 6.63 (1
H, dd, J=2.6 Hz), 6.58 (1 H, dd, J=8.1 and 2.6 Hz),
5.18 (1 H, t, J=7.3 Hz), 4.65 (1 H, br s, OH), 2.28 (2
H, t, J=7.4 Hz), 2.20 (3 H, s), 2.12 (2 H, q, J=7.3
Hz), 1.43 (2 H, sextet, J=7.3 Hz), 1.34–1.20 (4 H, m),
0.94 (3 H, t, J=7.3 Hz), 0.87 (3 H, t, J=6.8 Hz); 13C
l 153.68, 140.09, 137.39, 136.93, 130.09, 129.69, 116.48,
111.91, 31.71, 30.36, 30.11, 23.02, 22.83, 20.04, 14.01,
13.90; MS (m/z) 232 [M+], 217, 203, 190, 175, 161,
148, 147. A minor set of the 1H-NMR signals at-
tributable to the presence of the other geometric isomer
(isomer ratio=84:16) at l (partial) 6.80 (1 H, d, J=8.1
Hz), 6.66 (1 H, d, J=2.6 Hz), and 5.42 (1 H, tt, J=7.3
and 1.1 Hz) was also observed.
1
1581, 1226, 857, 812 cm−1; H l 6.96 (1 H, d, J=8.1
Hz), 6.68 (1 H, d, J=2.6 Hz), 6.65 (1 H, dd, J=8.1
and 2.6 Hz), 5.60 (1 H, s), 5.54 (1 H, tt, J=3.6 and 1.8
Hz), 2.25 (3 H, s), 2.21–2.14 (4 H, m), 1.82–1.65 (4 H,
m); 13C l 153.60, 138.17, 137.47, 136.66, 129.37, 125.76,
116.61, 112.23, 30.32, 25.38, 23.09, 22.15, 19.84; MS
(m/z) 188 (M+), 173, 160, 159, 145.
4.3. 1-(1-Cyclohexenyl)-5-iodo-2-methyl-4-(2-
propenyl)benzene (27)
The same procedure was repeated as described for 26
except that after 15 h of stirring following the introduc-
tion of trimethyltin chloride, the mixture was cooled to
−78°C. A solution of a 1.6 M n-butyllithium in hex-
anes (1.25 ml, 2.0 mmol) was added with a syringe.
After 15 min, the reaction mixture was transferred via
cannula to a flask containing 0.452 g (2.20 mmol) of
CuBr·SMe2 and 15 ml of THF maintained at −78°C.
After l h at −78°C, 0.726 g (6.00 mmol) of allyl
bromide was introduced dropwise, and the reaction
mixture was stirred at −78°C for 1 h before it was
allowed to warm to r.t. A solution of 1.02 g of iodine
(4.00 mmol) in 10 ml of diethyl ether was added via
cannula. The resulting mixture was stirred at r.t. for 1
h followed by the addition of a saturated Na2S2O3
solution to destroy excess I2. An additional 30 ml of
water and 40 ml of Et2O were added, and the organic
layer was then separated, washed with a saturated NaCl
solution, dried over MgSO4, and concentrated. The
residue was purified by column chromatography (silica
gel/hexanes) to afford 0.203 g (0.60 mmol, 30%) of 27
4.5. trans-(9)-4b,5,6,7,8,8a,9,10-Octahydro-2-
phenanthrenol (34)
The same procedure was repeated as described for 26
except that 0.292 g (2.00 mmol) of 3,4,10-undecatrien-1-
yne (44) was used to prepare 31. To facilitate purifica-
tion of 34, the products isolated after column
chromatography were treated with an excess of a 2.0 M
solution of BH3·SMe2 in THF followed by oxidation
with an alkaline 30% H2O2 solution. This treatment
allowed conversion of undesired side products contain-
ing a terminal carbon–carbon double bond to more
polar adducts having a hydroxyl group. Further purifi-
cation by column chromatography afforded 0.023 g
(0.11 mmol, 6%) of 34 [23] as a white solid: IR 3302,
1
1610, 1247, 802 cm−1; H l 7.14 (1 H, d, J=8.3 Hz),
6.61 (1 H, dd, J=8.4 and 2.9 Hz), 6.54 (1 H, d, J=2.8
Hz), 4.51 (1 H, br s, OH), 2.84 (1 H, ddd, J=17.0, 11.5
and 5.9 Hz), 2.73 (1 H, ddd, J=16.8, 6.0 and 2.4 Hz),
2.39 (1 H, dm, J=12.9 and 3.4 Hz), 2.18 (1 H, td,
J=10.7 and 2 Hz), 1.93–1.84 (1 H, m), 1.8–1.7 (3 H,
m), 1.5–1.1 (6 H, m); 13C l 153.09, 138.68, 133.10,
126.61, 115.16, 112.62, 43.24, 40.80, 34.24, 31.19, 30.64,
30.01, 26.89, 26.31; MS (m/z) 202 [M+], 174, 159, 145.
1
as a yellow oil: IR (neat) 991, 914 cm−1; H l 7.54 (1
H, s), 7.00 (1 H, s), 5.96 (1 H, ddt, J=16.6, 10.3, and
6.6 Hz), 5.55 (1 H, tt, J=5.5 and 2.8 Hz), 5.14 (1 H,

114
Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
1
The assignment of the trans geometry to 34 is based on
the coupling constant of ca. 10.7 Hz for the two anti
hydrogen atoms with the benzylic methine hydrogen at
IR (neat) 3341, 1606, 1581, 1230, 817 cm−1; H l 6.91
(1 H, d, J=8.3 Hz), 6.70 (1 H, d, J=2.6 Hz), 6.61 (1
H, dd, J=8.1 and 2.8 Hz), 5.21 (1 H, t, J=7.3 Hz),
5.17 (1 H, br s, OH), 2.52 (2 H, t, J=8.0 Hz), 2.29 (2
H, t, J=7.3 Hz), 2.15 (2 H, q, J=7.3 Hz), 1.6–1.5 (2
H, m), 1.45 (2 H, sextet, J=7.3 Hz), 1.37–1.23 (8 H,
m), 0.97 (3 H, t, J=7.3 Hz), 0.90 (3 H, t, J=6.7 Hz),
0.87 (3 H, t, J=6.9 Hz); 13C l 153.73, 141.96, 140.03,
137.12, 130.41, 129.80, 115.30, 111.93, 32.94, 32.27,
31.98, 31.28, 30.41, 30.14, 23.03, 22.86, 22.54, 14.02,
13.99, 13.90; MS (m/z) 288 [M+], 259, 231, 217, 189,
175, 161; HRMS calc. for C20H32O 288.2453, found
288.2442. Anal. Calc. for C20H32O: C, 83.27; H, 11.18.
Found: C, 83.15; H, 11.19. A minor set of the 1H-NMR
signals (partial) at l 6.81 (1 H, d, J=8.3 Hz), 6.74 (1
H, d, J=2.6 Hz), 6.64 (1 H, dd, J=8 and 2.6 Hz), and
5.45 (1 H, tt, J=7.1 and 1.2 Hz) attributable to the
presence of the other geometric isomer (isomer ratio=
87:13) was also observed.
1
2.18 ppm. The H-NMR chemical shift of the benzylic
methine hydrogen and the 13C-NMR chemical shifts of
the aliphatic carbons are also consistent with the as-
signment of the trans geometry to 34 when compared
with those of trans-1,2,3,4,4a,9,10,10a-octahydrophe-
nanthrene reported previously [3a]. A minor set of the
1H-NMR signals (partial) attributable to 4-[(1E)-1,6-
heptadienyl]-3-methylphenol (ca. 1%) at l 7.28 (1 H, d,
J=9 Hz), 6.48 (1 H, dt, J=15.8 and 1.5 Hz), 5.94 (1
H, dt, J=15.6 and 6.9 Hz) was also observed.
4.6. 4-(1-Butyl-1-pentenyl)-3-pentylphenol (42)
The following procedure for the preparation of 42 is
representative. To 0.352 g (2.00 mmol) of 5-butyl-3,4-
nonadien-1-yne (35) in 20 ml of THF at −78°C under
a nitrogen atmosphere was added 0.80 ml (2.0 mmol) of
a 2.5 M solution of n-butyllithium in hexanes. After 30
min at −78°C, 0.416 g (2.00 mmol) of B-methoxydicy-
clohexylborane in 10.0 ml of THF was introduced via
cannula. After 1.5 h of stirring at −78°C, 0.33 ml (2.67
mmol) of BF3·OEt2 was added with a syringe, and the
mixture was allowed to warm to r.t. Solvent was re-
moved in vacuo, and the remaining yellow viscous
residue was dissolved in 30 ml of pentane. The solution
was transferred to centrifuge tubes via cannula for
centrifugation. The supernatant liquid was then trans-
ferred via cannula to a flask. Pentane was removed in
vacuo to furnish 36 as a colorless viscous liquid. Anhy-
drous THF (35 ml) was added, and the solution was
cooled to −78°C. To a second flask containing 0.202 g
(2.1 mmol) of 1,2-heptadiene in 15 ml of THF at
−78°C was added 0.80 ml (2.0 mmol) of a 2.5 M
solution of n-butyllithium in hexanes. After 30 min of
stirring at −78°C, 1-lithio-1,2-heptadiene (37) was
added via cannula to the flask containing 36. After 1 h
of stirring at −78°C, the mixture was allowed to warm
to r.t. and stirred for an additional 3 h. The mixture
was then cooled to 0°C, and 2.0 ml of a 1.0 M solution
of trimethyltin chloride in THF was introduced with a
syringe. After 14 h of stirring at r.t., the mixture was
transferred via cannula to a flask containing 2 ml of
30% H2O2, 2.0 ml of a 6 N NaOH solution, and 15 ml
of methanol at 0°C. The reaction mixture was heated at
50°C for 1 h. Glacial acetic acid (2 ml) was added, and
the mixture was heated at 50°C for an additional 2 h
before it was allowed to cool to r.t. The organic layer
was separated, and the aqueous layer was extracted
with pentane (3×20 ml). The combined organic layers
were washed with water, dried over MgSO4, and con-
centrated. The residue was purified by column chro-
matography (silica gel/20% Et2O in hexanes) to furnish
0.351 g (1.22 mmol, 61%) of 42 as a light yellow liquid:
4.7. 1-(1-Butyl-1-pentenyl)-2-pentylbenzene (43)
The same procedure was repeated as described for 42
except that the reaction mixture was treated with acetic
acid directly. Purification by column chromatography
(silica gel/hexanes) furnished 0.310 g (1.14 mmol, 57%)
of 43 as a yellow oil: IR (neat) 1457, 758 cm−1; H l
1
7.24–7.20 (2 H, m), 7.19–7.11 (1 H, m), 7.07 (1 H, dm,
J=6.9 and 1.3 Hz), 5.28 (1 H, t, J=7.3 Hz), 2.61 (2 H,
t, J=8.0 Hz), 2.38 (2 H, t, J=7.3 Hz), 2.21 (2 H, q,
J=7.3 Hz), 1.63 (2 H, m), 1.50 (2 H, sextet, J=7.3
Hz), 1.42–1.28 (8 H, m), 1.02 (3 H, t, J=7.3 Hz), 0.94
(3 H, t, J=6.7 Hz), 0.91 (3 H, t, J=6.7 Hz); 13C l
144.31, 140.63, 140.20, 129.60, 129.34, 128.75, 126.30,
124.97, 32.98, 32.19, 32.10, 31.55, 30.49, 30.14, 23.06,
22.91, 22.59, 14.05, 13.99. 13.92; MS (m/z) 272 [M+],
215, 201, 173, 159, 145, 117; HRMS Calc. for C20H32
1
272.2504, Found 272.2481. A minor H-NMR signal of
the alkenyl hydrogen of the other geometric isomer at l
5.50 (tt, J=7.1 and 1 Hz) was also observed.
4.8. (9)-10i-Butyl-4bh,5,6,7,8,8ai,9,10-octahydro-2-
phenanthrenol (53), 4-[(1E)-1,6-heptadienyl]-3-
pentylphenol (54), and 4-(6-heptenyl)-3-
[(E)-1-pentenyl]phenol (55)
The same procedure was repeated as described for 42
except that 0.292 g (2.0 mmol) of 44 was used. Purifica-
tion by column chromatography (silica gel/10% diethyl
ether in hexanes) furnished 0.232 g (0.90 mmol, 45%) of
a mixture of 53 (20%), 54 (10%) and 55 (15%) as a
colorless liquid. The amounts of 53, 54 and 55 in the
mixture were determined by integration of the 1H-
NMR spectrum. It was possible to separate 53 and 55
from the mixture by HPLC. A fraction containing
predominantly 54 was also obtained. 53: IR (neat)

Q. Zhang, K.K. Wang / Journal of Organometallic Chemistry 581 (1999) 108–115
115
1
3342, 1609, 1582, 1244, 733 cm−1. H l 7.13(1 H, d,
J=8.8 Hz), 6.63 (1 H, d, J=8 Hz), 6.60 (1 H, s), 4.77
(1 H, br s, OH), 2.66 (1 H, m), 2.39 (1 H, dm, J=12
and 3 Hz), 2.12 (1 H, tm, J=11 and 3 Hz), 1.94–1.1
(16 H, m), 0.92 (3 H, t, J=7.1 Hz); 13C l 153.13,
143.85, 132.76, 126.21, 115.38, 112.71, 43.74, 38.21,
37.84. 35.61, 34.34, 33.92, 30.96, 30.38, 26.92, 26.43,
22.84, 14.13; MS (m/z) 258 [M+], 201, 174, 159, 145,
Chem. Rev. 89 (1989) 1681. (i) N. Martin, C. Seoane, M.
Hanack, Org. Prep. Proc. Int. 23 (1991) 237. (j) W. Oppolzer, in:
B.M. Trost, I. Fleming (Eds.), Comprehensive Organic Synthe-
sis, Vol. 5, Pergamon Press, New York, 1991, p. 385. (k) T.-S.
Chou, Rev. Heteroatom. Chem. 8 (1993) 65.
[2] Y. Ito, M. Nakatsuka, T. Saegusa, J. Am. Chem. Soc. 102 (1980)
863.
[3] (a) K.C. Nicolaou, W.E. Barnette, P. Ma, J. Org. Chem. 45
(1980) 1463. (b) W. Oppolzer, D.A. Roberts, T.G.C. Bird, Helv.
Chem. Acta 62 (1979) 2017.
[4] (a) B.D. Lenihan, H. Shechter, J. Org. Chem. 63 (1998) 2072. (b)
Y.W. Andemichael, Y.G. Gu, K.K. Wang, J. Org. Chem. 57
(1992) 794. (c) K.K. de Fonseka, J.J. McCullough, A.J.
Yarwood, J. Am. Chem. Soc. 101 (1979) 3277.
1
133. 54: H (partial) l 7.29 (1 H, d, J=8.2 Hz), 6.60 (2
H, m), 6.51 (1 H, dt, J=15.4 and 1.6 Hz), 5.94 (1 H,
dt, J=15.4 and 6.9 Hz); 13C l 154.36, 141.50, 138.76,
130.22, 129.43, 127.11 (2 carbons), 115.86, 114.55,
112.97, 33.32, 33.20, 32.65, 31.72, 30.46, 28.73, 22.53,
14.03. 55: IR (neat) 3354, 1640, 1607, 1578, 1245, 993,
964, 909, 867, 821 cm−1; 1H l 6.96 (1 H, d, J=8.2 Hz),
6.90 (1 H, d, J=2.6 Hz), 6.62 (1 H, dd, J=8.3 and 2.7
Hz), 6.54 (1 H, dt, J=15.7 and 1.1 Hz), 6.05 (1 H, tt,
J=15.6 and 6.9 Hz), 5.80 (1 H, ddt, J=17.0, 10.2 and
6.6 Hz), 4.98 (1 H, dm, J=17 and 2 Hz), 4.93 (1 H,
dm, J=10 and 1 Hz), 4.73 (1 H, br s, OH), 2.56 (2 H,
t, J=7.7 Hz), 2.19 (2 H, qd, J=7.3 and 1.7 Hz), 2.04
(2 H, qm, J=6.6 and 1 Hz), 1.6–1.3 (8 H, m), 0.95 (3
H, t, J=7.3 Hz); 13C l 153.57, 139.08, 137.74, 132.58,
132.22, 130.51, 127.27, 114.20, 113.77, 112.24, 35.31,
33.71, 32.49, 31.06, 28.94, 28.75, 22.55, 13.68; MS (m/z)
258 (M+), 229, 215, 201, 187, 175, 145, 133. The
assignment of the trans ring junction to 53 is based on
the 1H-NMR chemical shift of the benzylic methine
hydrogen at 2.12 ppm as observed in the case of 34.
The structures of 54 and 55 were assigned on the basis
[5] P.G. Sammes, Tetrahedron 32 (1976) 405.
[6] G. Quinkert, H. Stark, Angew. Chem. Int. Ed. Engl. 22 (1983)
637.
[7] J.M. Hornback, R.D. Barrows, J. Org. Chem. 47 (1982) 4285.
[8] (a) K.K. Wang, Chem. Rev. 96 (1996) 207. (b) K.K. Wang, Z.
Wang, A. Tarli, P. Gannett, J. Am. Chem. Soc. 118 (1996)
10783. (c) Y.W. Andemichael, Y. Huang, K.K. Wang, J. Org.
Chem. 58 (1993) 1651.
[9] D.A. Ben-Efraim, F. Sondheimer, Tetrahedron Lett. (1963) 313.
[10] C.M. Bowes, D.F. Montecalvo, F. Sondheimer, Tetrahedron
Lett. (1973) 3181.
[11] S. Braverman, Y. Duar, Tetrahedron Lett. (1978) 1493.
[12] (a) U.H. Brinker, I. Fleischhauer, Angew. Chem. Int. Ed. Engl.
18 (1979) 396. (b) W.H. Okamura, R. Peter, W. Reischl, J. Am.
Chem. Soc. 107 (1985) 1034. (c) Y.W. Andemichael, K.K. Wang,
J. Org. Chem. 57 (1992) 796. (d) K.K. Wang, Q. Zhang, J. Liao,
Tetrahedron Lett. 37 (1996) 4087.
[13] (a) J. Hooz, R. Mortimer, Tetrahedron Lett. (1976) 805. (b) G.
Zweifel, S.J. Backlund, J. Organomet. Chem. 156 (1978) 159. (c)
B. Wrackmeyer, C. Bihlmayer, M. Schilling, Chem. Ber. 116
(1983) 3182. (d) K.K. Wang, K.-H. Chu, J. Org. Chem. 49
(1984) 5175. (e) K.-H. Chu, K.K. Wang, J. Org. Chem. 51 (1986)
767. (f) K.K. Wang, K.-H. Chu, Y. Lin, J.-H. Chen, Tetrahe-
dron 45 (1989) 1105. (g) Z. Wang, K.K. Wang, J. Org. Chem. 59
(1994) 4738. (h) A. Tarli, K.K. Wang, J. Org. Chem. 62 (1997)
8841. For reviews of chemistry of organoborates, see: (i) M.
Vaultier, B. Carboni, in: E.W. Abel, F.G.A. Stone, G. Wilkinson
(Eds.), Comprehensive Organometallic Chemistry II. A Review
of the Literature 1982–1994, Vol. 11, Pergamon Press, Oxford,
1995, pp. 227–229. (j) E.-I. Negishi, J. Organomet. Chem. 108
(1976) 281.
1
of the H-NMR chemical shifts of the aromatic hydro-
gens at the meta position. The chemical shift of the
meta aromatic hydrogen of 54 at 7.29 ppm is essentially
identical to that of 4-[(1E)-1,6-heptadienyl]-3-
methylphenol at 7.28 ppm.
Acknowledgements
[14] (a) F. Johnson, Chem. Rev. 68 (1968) 375. (b) R.W. Hoffmann,
Chem. Rev. 89 (1989) 1841.
[15] H.C. Brown, J.A. Sinclair, J. Organomet. Chem. 131 (1977) 163.
[16] (a) R.B. Woodward, R. Hoffmann, J. Am. Chem. Soc. 87 (1965)
395. (b) W.H. Okamura. A.R. De Lera, in: B.M. Trost, I.
Fleming (Eds.), Comprehensive Organic Synthesis, Vol. 5, Perga-
mon Press, New York, 1991, p. 699.
[17] (a) S. Braverman, Y. Duar, D. Segev, Tetrahedron Lett. (1976)
3181. (b) S. Braverman, D. Segev, J. Am. Chem. Soc. 96 (1974)
1245.
The financial support of the National Science Foun-
dation (CHE9618676) is gratefully acknowledged. The
authors thank Professor Harold Shechter for helpful
discussion regarding the assignment of geometry for 30
and related adducts.
[18] H. Hopf, I. Bohm, J. Kleinschroth, Org. Syn. 60 (1981) 41.
[19] G.W. Kramer, H.C. Brown, J. Organomet. Chem. 73 (1974) 1.
[20] L. Skattebol, J. Org. Chem. 31 (1966) 2789.
References
[1] (a) W. Oppolzer, Synthesis (1978) 793. (b) W. Oppolzer, Hetero-
cycles 14 (1980) 1615. (c) R.L. Funk, K.P.C. Vollhardt, Chem.
Soc. Rev. 9 (1980) 41. (d) J.J. McCullough, Acc. Chem. Res. 13
(1980) 270. (e) P. Magnus, T. Gallagher, P. Brown, P. Pap-
palardo, Acc. Chem. Res. 17 (1984) 35. (f) A.G. Fallis, Can. J.
Chem. 62 (1984) 183. (g) J.L. Charlton, M.M. Alauddin, Tetra-
hedron 43 (1987) 2873. (h) U. Pindur, H. Erfanian-Abdoust,
[21] L. Brandsma, H.D. Verkruijsse, Synthesis of Acetylenes, Allenes
and Cumulenes, Elsevier, Amsterdam, 1981, p. 157.
[22] (a) H.C. Brown, U.R. Khire, U.S. Racherla, Tetrahedron Lett.
34 (1993) 15. (b) H.C. Brown, U.R. Khire, G. Narla, U.S.
Racherla, J. Org. Chem. 60 (1995) 544.
[23] B. Alcaide, J.I. Luengo, F. Fernandez, An. Quim. Ser. C 77
(1981) 200.
.