A convenient method for the generation of allylic dihaloboranes and diallyl(chloro)borane and their application in the allylboration of alkenes and acetylenes

Article abstract of DOI:10.1002/ejoc.200500391

A convenient approach to the highly reactive allylic dihaloboranes and diallyl(chloro)borane based on exchange reactions between BHal₃ (Hal = Cl, Br) and allylic triorganoboranes (allyl, cinnamyl and 2- methylenecyclobutane derivatives) has bee

Full text of DOI:10.1002/ejoc.200500391

FULL PAPER
A Convenient Method for the Generation of Allylic Dihaloboranes and
Diallyl(chloro)borane and Their Application in the Allylboration of Alkenes
and Acetylenes
[a]
[a]
[a]
[a]
Yuri N. Bubnov,* Nikolai Y. Kuznetsov, Fedor V. Pastukhov, and Vadim V. Kublitsky
Keywords: Alkenes / Alkynes / Boron / Allyl(halo)boranes / Exchange reactions / Allylboration
A convenient approach to the highly reactive allylic dihalo-
boranes and diallyl(chloro)borane based on exchange reac-
tions between BHal (Hal = Cl, Br) and allylic triorganobor-
3
anes (allyl, cinnamyl and 2-methylenecyclobutane deriva-
tives) has been developed. The compounds thus generated
readily react with terminal alkenes and acetylenes to form
the corresponding cis-1,2-allylboration products. These pro-
ducts were isolated by standard techniques and transformed
into boronates (boron amides). Deboronation of these pro-
ducts led to 1,4-pentadiene derivatives or unsaturated
alcohols. 2-Substituted 1,4-pentadienyl(dichloro)boranes ob-
tained from acetylenes underwent intramolecular chlorobor-
ation at a moderate temperature to form 5-chloro-2-borinene
derivatives.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
Br).[10,11] Wardell and co-workers have shown through a
NMR study that exchange between allylic tin derivatives
and haloboron compounds proceeds with retention of the
Introduction
The 1,2-allylboration of organic compounds containing
multiple bonds (C=O, C=S, C=N, C=C, N=O, CϵC,
CϵN) is a general reaction that proceeds with allylic trans-
position via a cyclic six-membered transition state.
more the multiple bond is polarized or strained the easier
the allylboration. 1,2-Addition reactions of allylic trior-
ganylboranes, such as triallyl-, trimethallyl- and tricrotyl-
boranes, or allyl(diorganyl)boranes to certain olefins, cyclo-
propenes and terminal acetylenes have successfully been
[
12]
configuration of the allylic group.
However, transfer of
allylic groups from tin to boron also occurs with allylic
transposition, presumably via a six-membered cyclic transi-
[
1–3]
The
[
11b,c,13]
tion state.
α-Methylated allylic boranes formed ini-
[
2]
tially from crotyl- or prenylstannanes rearrange to the ther-
modynamically more stable crotyl and prenylboranes.[
The disadvantage of this method is the use of toxic or-
ganotin derivatives. Therefore we have developed an envi-
ronmentally friendly method based on the exchange reac-
tion between the corresponding allylic triorganoboranes
11,13]
[
1c,2,4]
used in the preparation of various 1,4-dienes,
cyclo-
[
1c,5]
[6]
propanes,
tri- and tetravinylmethanes, allyl methyl
[
7]
[8]
ketone derivatives, 1,4-enynes, as well as cyclohexane
and BCl or BBr . The principle of this process has been
and cyclohexene compounds.[ In the case of RCϵC–
1c]
3
3
known since 1975 when the reactions of triallyl- and tri-
MRЈ (M = Si, Sn, Ge), a competition between 1,1- and
3
crotylborane with an excess of BCl were investigated by
3
1,2-allylboration takes place, 1,1-allylboration proceeding
[
14]
NMR spectroscopy.
[
9]
with retention of configuration of the allylic group.
As expected, highly electrophilic allyldichloro- and allyl-
dibromoboranes possess high reactivity and selectivity in
the 1,2-addition to alkenes, certain 1,3-dienes and al-
[
10]
kynes. No 1,4-addition to cyclic and linear 1,3-dienes has
been observed.
Allylic dihaloboranes are unstable and should be used
for further transformations as quickly as possible. The half-
Results and Discussion
Allyl(dichloro)borane (1a, 11B NMR: δ = 61.4 ppm)[11a]
and diallyl(chloro)borane (1c, B NMR: δ = 73.8 ppm) are
cleanly obtained in situ by adding of triallylborane to a co-
oled (–10 °C) solution of 1  BCl in hexane in a ratio of
life of these compounds in dilute CDCl ranges from several
11
3
days (allylic difluoroboranes) to 3–7 minutes (allylic dibro-
[
11a]
moboranes).
A general approach to the synthesis of al-
3
lyldihaloboranes involves a transmetallation reaction be-
tween allylic tin compounds and BHal3 (Hal = F, Cl,
1
:2 and 2:1, respectively. Monitoring the reactions with
NMR spectroscopy shows that they are complete within
min. Allyl(dibromo)borane (1b, solution in hexane) can
5
[
a] A. N. Nesmeyanov Institute of Organoelement Compounds,
be generated from triallylborane and BBr (1:2) at –40 °C
in hexane (Scheme 1).
Russian Academy of Sciences,
3
Vavilov 28, 119991, Moscow, Russia
Eur. J. Org. Chem. 2005, 4633–4639
DOI: 10.1002/ejoc.200500391
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4633

Y. N. Bubnov, N. Y. Kuznetsov, F. V. Pastukhov, V. V. Kublitsky
FULL PAPER
(–20 °C Ǟ room temp., 2 h) produces monochloroborane 4
and Et NHCl (Scheme 3).
3
Scheme 1.
Scheme 3.
The reactions of 2-borinenes (3a or 3b) with 2 equiv. of
Allyl(dichloro)borane (1a) generated as above was then
allowed to react with phenylacetylene or 1-pentyne in hex-
ane at –15 °C (Scheme 2). After evaporation of the solvent,
two pairs of compounds were detected by NMR spec-
troscopy in the each case: the corresponding products of
iPrOH and Et N produce diisopropyl 1,4-pentadienyl-
3
boronates 5 in approximately 80% yield while treatment
with lithium diethylamide affords the corresponding bis(di-
ethylamino)boranes 6 (Scheme 4).
All the allylboration products (2, 3 and 5) undergo debo-
ronation with base (5  NaOH, 20 °C) to furnish 2-phenyl-
11
the cis-allylboration of the acetylene triple bond, 2a ( B
1
1
NMR: δ = 52.5 ppm) or 2b ( B NMR: δ = 51.1 ppm), and
a or 3b, which result from intramolecular chloroboration
(
7a) or 2-propyl-1,4-pentadiene (7b), respectively.
We found that allyl(dichloro)borane is also generated by
3
of the terminal C=C bond in 2a or 2b. Refluxing the mix-
ture of 2 and 3 in hexane for 2 h or distillation gives rise to
the interaction between allyl(dipropyl)borane and BCl3.
Further treatment of the mixture with phenylacetylene pro-
1
1
2
(
-borinene derivatives 3a ( B NMR: δ = 62.3 ppm) or 3b
1
duces a mixture of 2a and 3a ( H NMR spectroscopy).
1
1
B NMR: δ = 64.8 ppm) with 90–96% purity. The 2-bor-
Diene 7a (72%) was obtained after deboronation of the re-
action mixture with acetic acid (Scheme 5).
inenes seem to be in equilibrium (cyclization ↔ β-elimi-
nation) with the acyclic form 2 (Յ4–10%) (Scheme 2).
Scheme 5.
This approach is equally suitable for the generation of
more complicated allylic dihaloboranes. Thus, cinnamyl(di-
propyl)borane (8) (prepared as only the trans isomer from
Scheme 2.
Nucleophilic reagents were found to open the cyclic sys- cinnamyllithium and Pr BOMe) when mixed with BCl af-
2
3
tem of 3a (β-elimination), leading to the recovery of the fords cinnamyl(dichloro)borane (9) (Scheme 6). It should
1,4-diene-type structure. Thus treatment of “pure” 3a with be stressed that transfer of allylic groups from one boron
1
equiv. of 2-propanol in the presence of 1 equiv. of Et N atom to another in these exchange reactions proceeds with
3
Scheme 4.
634
4
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 4633–4639

Allylhaloboranes and the Allylboration of Alkenes and Acetylenes
FULL PAPER
Scheme 6.
Scheme 7.
allylic transpositions, probably via a six-membered cyclic
transition state. However, initially formed 1-phenylallyl-
(dichloro)borane (9a) rearranges to the thermodynamically
preferred cinnamyl derivative 9, the isomer with less substit-
uents on the α-carbon atom.[ The latter allylborates phen-
ylacetylene with rearrangement (10) to form the product(s)
14]
11 and/or 12, which undergo protolytic deboronation to
give 2,3-diphenyl-1,4-pentadiene (13).
It was previously reported by Singleton et al.[
10a]
that the
allylboration of allylic silanes with borane 1a is a facile pro-
cess that leads to the corresponding adducts in high yields
(up to 93%). We have investigated a similar reaction with a
mixture of isomeric dichloroboranes generated from BCl3
Scheme 8.
and a dynamic mixture of 2-methylenecyclobutyl- (14a) and
15]
1
-cyclobutenylmethyl(dipropyl)borane (14b)[ (Scheme 7).
Further oxidation of the mixture with alkaline hydrogen
peroxide led to two silylated carbinols 15 and 16 in a 1:2
ratio. Again, addition to the double bond of allylsilane oc-
curs with allylic rearrangement. The predominant product
through intramolecular allylboration of the terminal double
bond. The latter was transformed into borinate 21 by treat-
ment with a mixture of 2-propanol and triethylamine.
16 is obtained from the thermodynamically more stable 2-
methylenecyclobutyl(dichloro)borane.
Allyldibromoborane (1b) is much more reactive than the
corresponding dichloride 1a and adds to alkenes and 1,3-
[
10]
dienes. We tested 1b generated from BBr and triallylbor-
3
ane in the reaction with styrene (Scheme 8). 1,2-Addition
(hexane, –5 °C) is complete within 2 h. The dibromoborane
17 formed was transformed (without isolation) into bo-
ronate 18 by treatment with a MeOH/Et N mixture. Vac-
3
uum distillation affords pure 18 in 74% yield.
Our attempts to allylborate internal acetylenes (octyne
or tolane) with 1a or 1b failed.
Diallyl(chloro)borane (1c) also readily allylborates 1-
pentyne (Scheme 9) to form the borane 19 which is trans-
formed by distillation into the cyclic product 20 (85%) Scheme 9.
Eur. J. Org. Chem. 2005, 4633–4639
www.eurjoc.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4635

Y. N. Bubnov, N. Y. Kuznetsov, F. V. Pastukhov, V. V. Kublitsky
FULL PAPER
δ = 36.28 (br. CH
2 2
B), 41.8 (CH ), 58.14 (CHCl), 126.99 (CHPh),
Conclusions
1
29.2 (2 CHPh), 129.0 (2 CHPh), 130.20 (CPh), 168.7 (CPh=) ppm.
B NMR (64 MHz, CDCl ): δ = 62.3 (s, ClBR ) ppm.
3 2
1
1
A convenient method for the generation of various highly
reactive allylic dihaloboranes and diallyl(halo)boranes in-
volves facile exchange reactions between allylic triorgano-
Dichloro[(1E)-2-propyl-1,4-pentadienyl]borane
Dichloro-3-propyl-2-borinene (3b): Compounds 2b and 3b were pre-
pared from 1-pentyne (2.04 g, 0.03 mol) and a solution of 1a
(2b)
and 1,5-
boranes and BCl or BBr . Allylic haloboranes thus gener-
3
3
ated readily allyborate terminal acetylenes and alkenes. Al- (0.03 mol) in hexane according to the above procedure. Com-
lylboration products can be transformed into different or- pounds 2b and 3b were initially formed in a ratio of 2:1. Distillation
ganoboron compounds (esters, amides, boracyclanes) or of the mixture in vacuo gave compounds 2b and 3b in a 10:90 ratio
(
5.0 g, 87%) as a colorless liquid, b.p. 88–89 °C (1 Torr).
their deboronation products, such as unsaturated alcohols
and 1,4-dienes.
1
2b: H NMR (200 MHz, CDCl ): δ = 0.94 (t, J = 7.3 Hz, 3 H), 1.6
3
(
6
tq, J = 7.6, 7.3 Hz, 2 H), 2.25 (t, J = 7.6 Hz, 2 H), 3.38 (d, J =
.6 Hz, 2 H), 5.08 (dd, J = 8.2, 1.5 Hz, 1 H), 5.15 (dd, J = 14.8,
1.5 Hz, 1 H), 5.72 (ddt, J = 14.8, 8.2, 6.6 Hz, 1 H), 5.96 (s, 1
Experimental Section
1
3
H) ppm. C NMR (50 MHz, CDCl
4
3
): δ = 13.72, 20.90, 38.72,
General: All reactions were performed in dry argon. The solvents
were purified by standard techniques. Tetrahydrofuran (THF), di-
ethyl ether and toluene were distilled from sodium-benzophenone
ketyl. Hexane was distilled and stored over sodium. NMR spectra
were recorded with Bruker AMX-400, Avance-300 and WP-200SY
instruments. Chemical shifts are given in δ (ppm) and J values in
Hz. Mass spectra were recorded with a Finnigan Polaris Q Ion
Trap spectrometer. Column chromatography was carried out on sil-
ica gel (Merck), 60–230 mesh. Allyltrimethylsilane and phenylacet-
ylene were obtained from Aldrich. Triallylborane was prepared in a
multigram scale following a procedure described in the literature.[
11
2.86, 116.87, 127.08, 134.94, 174.65 ppm. B NMR (64 MHz,
CDCl
3
): δ = 51.09 (s, Cl
2
BR) ppm.
): δ = 0.94 (t, J = 7.3 Hz, 3 H),
1
3
1
4
1
b: H NMR (200 MHz, CDCl
3
.59 (m, 2 H), 1.6 (dd, J = 17.6, 11.0 Hz, 1 H), 2.10 (dd, J = 17.6,
.6 Hz, 1 H), 2.34 (t, J = 7.5 Hz, 2 H), 2.57 (dd, J = 17.3, 7.0 Hz,
H), 2.75 (dd, J = 17.3, 4.7 Hz, 1 H), 4.35 (m, 1 H), 5.99 (s, 1
1
3
H) ppm. C NMR (50 MHz, CDCl
3.03, 42.7, 57.37, 128.05, 175.80 ppm. B NMR (64 MHz,
CDCl ): δ = 64.84 (s, ClBR ) ppm.
3
): δ = 13.62, 20.10, 35.61,
1
1
4
3
2
16]
1-Isopropoxy(chloro)boryl-2-phenyl-1,4-pentadiene (4): A mixture of
iPrOH (1.64 g, 2.1 mL, 27.4 mmol) and Et N (2.76 g, 3.8 mL,
7.4 mmol) in hexane (10 mL) was slowly added with rigorous stir-
ring to a solution of 3a (96% purity) (6.17 g, 27.4 mmol) in hexane
(40 mL) at –40 °C. An abundant precipitation of Et NHCl was ob-
3
Allyldichloroborane (1a): Triallylborane (4.5 mL, 0.025 mol) was
2
added to a solution of BCl
3
in hexane (1 , 50 mL, 0.05 mol) at
–
10 °C and the mixture was stirred for 15 min at this temperature.
11
3
B NMR (64 MHz): δ = 61.4 (s, Cl
Allyldibromoborane (1b): Triallylborane (3.48 g, 4.53 mL,
.026 mol) was added to a solution of BBr (13 g, 5 mL, 52 mmol)
2
B–R) ppm.
served. After complete addition the reaction mixture was stirred
for 2 h, the precipitate was filtered and washed with hexane
0
3
(
2×10 mL). Evaporation of the filtrate under reduced pressure and
in hexane (100 mL) at –70 °C with stirring. The reaction mixture
was warmed to –40 °C for 10 min and immediately used in allylbor-
ation reactions.
vacuum distillation of the residue yielded 4 (5.5 g, 82%) as a yellow
1
liquid; b.p. 110–112 °C (1 Torr). H NMR (200 MHz, CDCl
3
): δ =
1
6
1
.3 (d, J = 6.6 Hz, 6 H), 3.61 (d, J = 6.1 Hz, 2 H), 4.6 (sept, J =
.6 Hz, 1 H), 5.03 (dd, J = 9.8, 1.4 Hz, 1 H), 5.15 (dd, J = 17.0,
.4 Hz, 1 H), 5.8–6.03 (m, 1 H), 5.90 (s, 1 H), 7.30–7.60 (m, 5
Diallylchloroborane (1c): Triallylborane (8.7 mL, 0.05 mol) was
added to a solution of BCl
10 °C and stirred for 30 min. 11B NMR (64 MHz): δ = 73.8 (s,
ClBR ) ppm.
3
in hexane (1 , 25 mL, 0.025 mol) at
1
3
H) ppm. C NMR (50 MHz, CDCl ): δ = 24.57, 38.29, 65.69,
3
–
1
1
1
15.42, 126.33, 127.35, 128.38, 137.2, 144.32, 154.33 ppm.
NMR (64 MHz, C ): δ = 30.79 ppm. MS (70 eV, EI): 249 [M] ,
14 (27), 188 (23), 172 (56), 155 (20), 144 (58), 130 (53), 129 (84),
05 (70), 91 (46), 87 (66), 77 (62), 66 (42), 59 (50), 43 (100).
18BClO (248.6): calcd. C 67.65, H 7.30, B 4.35, Cl 14.26;
B
2
+
6
D
6
Dichloro[(1E)-2-phenyl-1,4-pentadienyl]borane (2a) and 1,5-
Dichloro-3-phenyl-2-borinene (3a): Phenylacetylene (8.2 mL,
2
1
0.075 mol) was rapidly added at –15 °C to a solution of 1a
14
C H
(0.075 mol) in hexane (prepared as indicated above). After addition
found C 67.51, H 7.24, B 4.33, Cl 14.15.
was complete the reaction mixture was allowed to warm to 0 °C
and stirred for 1 h. Then all volatiles were removed in vacuo at
ambient temperature and the residue was analyzed by 1H NMR
spectroscopy; two products 2a and 3a were detected in a ratio of
Diisopropyl (1E)-2-Phenyl-1,4-pentadienylboronate (5a): A mixture
of isopropyl alcohol (3.8 g, 4.9 mL, 64 mmol) and Et N (6.4 g,
3
8
.9 mL, 64 mmol) was slowly added dropwise with rigorous stirring
to a solution of the mixture 2a and 3a (4:96) (6.75 g, 0.03 mol) in
hexane (80 mL) at –20 °C. Et NHCl was formed as a precipitate.
1:1. Distillation of the mixture in vacuo gave compounds 2a and
3a in a 4:96 ratio (13.4 g, 95%), as a colorless liquid, b.p. 98–99 °C
3
The reaction mixture was stirred for 2 h at room temperature, fil-
tered and the precipitate was washed with hexane (2×10 mL). The
filtrate was evaporated and the residue distilled in vacuo. This pro-
(0.5 Torr).
1
2
a: H NMR (200 MHz, CDCl
3
): δ = 3.9 (d, J = 6.1 Hz, 2 H), 5.08
(
(
dd, J = 9.9, 1.4 Hz, 1 H), 5.25 (dd, J = 15.7, 1.4 Hz, 1 H), 5.91
ddt, J = 15.7, 9.9, 6.1 Hz, 1 H), 6.48 (s, 1 H,), 7.3–7.6 (m, 5
vided the boronate 5a (6.5 g, 80%) as a colorless liquid, b.p. 132–
1
1
7
5
1
6
33 °C (5 Torr). H NMR (400 MHz, CDCl
3
): δ = 7.49 (d, J =
13
H) ppm. C NMR (50 MHz, CDCl
3
): δ = 37.05 (CH
=), 126.27 (2 CHPh), 128.38 (CHPh), 128.5 (2 CHPh), 129.63
Ph), 135.27 (CH=), 167.0 (CPh) ppm. 11B NMR (64 MHz,
2
), 116.82
.2 Hz, 2 H), 7.35 (t, J = 7.2 Hz, 2 H), 7.28 (t, J = 7.2 Hz, 1 H),
.9 (ddt, J = 17, 9.0, 6.5 Hz, 1 H), 5.86 (sept, 1 H), 5.13 (dd, J =
7.1, 1.2 Hz, 1 H), 4.99 (dd, J = 9.0, 1.2 Hz, 1 H), 4.54 (sept, J =
(CH
2
(
C
3 2
CDCl ): δ = 52.5 (s, BCl ) ppm.
.0 Hz, 2 HOCHMe), 3.59 (d, J = 6.5 Hz, 2 H), 1.25 (d, JCH,Me
=
1
13
3
a: H NMR (200 MHz, C
6
D
6
): δ = 1.59 (dd, J = 17.6, 11.2 Hz, 1 6.2 Hz, 12 H) ppm. C NMR (50 MHz, CDCl
143.49 (CPh), 137.01 (CH=), 127.81 (2 CHPh), 127.10 (CHPh),
126.03 (2 CHPh), 120.09 (br. CH ), 115.44 (CH =), 65.29
3
): δ = 154.73 C,
H); 1.98 (dd, J = 17.6, 4.6 Hz, 1 H), 2.6 (ddd, J = 17.2, 9.5, 1.4 Hz,
1
1
H), 2.8 (dd, J = 17.2, 4.5 Hz, 1 H), 3.91 (m, 1 H), 6.44 (d, J =
B
2
11
.4 Hz, 1 H), 7.3–7.6 (m, 5 H) ppm. 13C NMR (50 MHz, CDCl
): (2 CHOiPr), 38.03 (CH
), 24.33 (2 CH3,OiPr) ppm. B NMR
3
2
4636
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 4633–4639

Allylhaloboranes and the Allylboration of Alkenes and Acetylenes
FULL PAPER
): δ = 146.22 C, 140.83 (CPh), 136.08
1
3
(
64 MHz, CDCl
3
): δ = 26.0 [s, R-B(OiPr)
2
] ppm. MS (70 eV, EI):
m/z (%) = 272 [M] , 188 (15), 170 (55), 143 (70), 129 (90), 105 (70),
7 (80), 77 (50), 69 (40), 59 (50), 43 (100). C17 (272.2): (CH
C NMR (50 MHz, CDCl
3
+
(CH=), 128.16 (2 CHPh), 127.35 (2 CHPh), 125.9 (CHPh), 116.35
8
H25BO
2
2
=), 113.02 (CH =), 39.43 (CH
2
2
) ppm.[17a]
calcd. C 75.01, H 9.26, B 3.97; found C 75.00, H 9.24, B 3.83.
Method B: Deboronation of the mixture of 2a and 3a (7.0 g,
0.03 mol) under alkaline conditions following the above procedure
(Method A) also provided 7a (2.8 g, 65%).
Diisopropyl (1Z)-2-Propyl-1,4-pentadienylboronate (5b): Compound
5b was obtained from 3b (90% purity, 5.70 g, 0.03 mol) and a mix-
ture of iPrOH (3.43 g, 0.06 mol) and NEt (5.76 g, 0.06 mol) ac-
cording to the procedure described above for the preparation of 5a.
3
Method C: A solution of allyl(dipropyl)borane (0.52 g, 0.68 mL,
3
.8 mmol) in hexane (1.5 mL) was added at –15 °C to a solution of
BCl (0.63 , 6.0 mL, 3.8 mmol) in hexane. The mixture was stirred
for 20 min at –10 to –5 °C, and then phenylacetylene (0.3 g,
.33 mL, 3.0 mmol) in hexane (2 mL) was rapidly added. The reac-
Distillation gave the boronate 5b (5.9 g, 83%) as a colorless liquid,
3
1
b.p. 58–60 °C (1 Torr). H NMR (200 MHz, CDCl
3
): δ = 0.90 (t, J
=
2
7.9 Hz, 3 H), 1.17 (d, J = 6.3 Hz, 12 H), 1.45 (qt, J = 7.9, 7.4 Hz,
H), 2.05 (t, J = 7.4 Hz, 2 H), 3.03 (d, J = 6.9 Hz, 2 H), 4.42 (sept,
0
tion mixture was stirred for 1 h at 0 °C, and then all volatiles were
removed under reduced pressure. The resulting light-yellow liquid
was treated with AcONa (1.55 g, 19 mmol) in AcOH (4 mL) and
refluxed for 1 h. After cooling the mixture was made alkaline with
NaOH (5 , 20 mL) and extracted with hexane (3×10 mL). The
J = 6.3 Hz, 2 H), 4.95 (d, J = 11.6 Hz, 1 H), 5.03 (d, J = 18.5 Hz,
13
1
H), 5.21 (s, 1 H), 5.70–5.90 (m, 1 H) ppm. C NMR (50 MHz,
CDCl ): δ = 13.73, 20.78, 24.42, 30.78, 39.71, 65.24, 117.0, 130.0,
37.37, 157.25 ppm. 11B NMR (64 MHz, CDCl
): δ = 24.77 [s,
B(OiPr) ] ppm. C14 (238.2): calcd. C 70.6, H 11.43, B 4.54;
found C 69.64, H 11.67, B 4.44.
3
1
-
3
2
H27BO
2
extracts were washed twice with a solution of NaHCO
dried with Na SO , evaporated. Flash chromatography in hexane
on silica gel furnished 7a (0.33 g, 72%).
3
(10%),
2
4
(
1E)-1-Bis(diethylamino)boryl-2-phenyl-1,4-pentadiene (6a): A sus-
pension of lithium diethylamide (0.065 mol) [freshly prepared from
Et NH (4.75 g, 6.73 mL, 0.065 mol) and BuLi (1.6 , 40.6 mL,
.065 mol) in hexane (50 mL)] was slowly added to a solution of
2
0
3
-Propyl-1,4-pentadiene (7b): A solution of NaOH (5 , 60 mL,
.3 mol) was added with stirring to a solution of a mixture 2b and
b (9.5 g, 0.05 mol) in hexane (50 mL). The reaction mixture was
2
0
the mixture of 2a and 3a (4:96) (7.0 g, 0.031 mol) in hexane (50 mL)
at –20 °C. The mixture was stirred for 15 min at –20 °C and then
for 2 h at ambient temperature. The precipitate was filtered off and
the filtrate was evaporated under reduced pressure. The residue was
distilled in vacuo to yield 6a (5.2 g 56%) as a yellow oil, b.p. 155–
stirred for 1 h until complete deboronation (green-flame test). The
organic layer was separated and the aqueous one was extracted
with hexane (3×15 mL) and the combined extracts dried with
K
2
CO
less liquid, b.p. 115–116 °C (760 Torr). H NMR (200 MHz,
CDCl ): δ = 0.92 (t, J = 8.1 Hz, 3 H), 1.48 (tq, J = 8.1, 8.4 Hz, 2
H), 2.03 (t, J = 8.4 Hz, 2 H), 2.75 (d, J = 7.4 Hz, 2 H), 4.71 (s,
H), 5.01 (s, 1 H), 5.07 (d, J = 5.9 Hz, 1 H), 5.70–6.00 (m, 1
3
. Distillation of the residue gave 7b (3.5 g, 64%) as a color-
1
1
7
6
1
2
57 °C (2 Torr). 1H NMR (400 MHz, CDCl
3
): δ = 7.50 (d, J =
3
.5 Hz, 2 H), 7.36 (t, J = 7.5 Hz, 2 H), 7.26 (t, J = 7.5 Hz, 1 H),
.13 (s, 1 H), 5.82 (ddt, J = 17.1, 10.0, 6.5 Hz, 1 H), 5.06 (dd, J =
7.1, 1.6 Hz, 1 H), 4.97 (d, J = 10.0 Hz, 1 H), 3.40 (d, J = 6.5 Hz,
H), 3.08 (q, J = 6.8 Hz, 8 H), 1.09 (t, J = 6.9 Hz, 12 H) ppm.
2
[17b]
H) ppm.
trans-Cinnamyl(dipropyl)borane (8): tBuLi (1.83 , 23.5 mL,
13
C NMR (50 MHz, CDCl
3
): δ = 144.28 (C), 143.42 (CPh), 136.1
4
6
3 mmol) was added to a stirred solution of allylbenzene (5.31 g,
mL, 45 mmol) in THF (40 mL) at –70 to –60 °C and stirring was
(
(
CH=), 128.04 (CHPh), 126.15 and 126.44 (2 CHPh), 115.43
1
1
CH
2
=), 42.66 (4 CH2,Et), 38.22 (CH
2
), 15.75 (4 CH3,Et) ppm.
] ppm. MS (70 eV,
EI): m/z (%) = 298 (4) [M] , 225 (20), 210 (90), 155 (10), 127 (20),
05 (15), 84 (50), 77 (15), 72 (30), 58 (100), 44 (50). C19
298.3): calcd. C 76.51, H 10.48, B 3.62, N 9.39; found C 76.75, H
0.25, N 9.30.
B
continued for 10 min and then for 40 min at –20 to –10 °C. The
reaction mixture was cooled to –70 °C and Pr BOCH (5 g,
3 mmol) was injected, the red color of the mixture being rapidly
NMR (64 MHz, CDCl
3
): δ = 34.4 [s, R-B(NEt )
2 2
+
2
3
4
1
(
1
H31BN
2
discharged. The reaction mixture was then allowed to warm to
room temperature and quenched with TMSCl (6.1 mL, 48 mmol).
The solvents were removed under reduced pressure; the oily residue
was stirred with hexane (20 mL) and supernatant was separated
from the precipitate of LiCl. The hexane solution was concentrated
and vacuum distillation of the residue gave borane 8 (6.6 g, 73%) as
(1Z)-1-Bis(diethylamino)boryl-2-propyl-1,4-pentadiene (6b): Com-
pound 6b (4.6 g, 59%), b.p. 131–132 °C (1 Torr) was obtained ac-
cording to the above procedure from 3b (90% purity) (5.70 g,
1
1
0.03 mol) and LiNEt
2
(0.06 mol). H NMR (200 MHz, CDCl
3
): δ
a colorless liquid, b.p. 99–100 °C (0.5 Torr). H NMR (400 MHz,
=
0.90 (t, J = 7.9 Hz, 3 H), 1.0 (t, J = 9.8 Hz, 12 H), 1.46 (qt, J = CDCl ): δ = 7.38–7.28 (m, 4 H), 7.20 (t, J = 7.2 Hz, 1 H), 7.41 (dt,
3
7
.9, 7.6 Hz, 2 H), 2.02 (t, J = 7.6 Hz, 2 H), 2.82 (d, J = 8.0 Hz, 2
J = 7.8, 15.6 Hz, 1 H), 6.32 (d, J = 15.6 Hz, 1 H), 2.34 (d, J =
7.8 Hz, 2 H), 1.54 (sext., J = 6.7 Hz, 4 H), 1.32 (t, J = 8.0 Hz, 4
H), 0.97 (t, J = 7.6 Hz, 6 H) ppm. C NMR (100 MHz, CDCl3):
δ = 138.30 (C), 129.49 (CH=), 128.26 (2 CHPh), 127.76 (CH=),
H), 2.98 (q, J = 9.8 Hz, 8 H), 4.98 (dd, J = 9.0, 1.8 Hz, 1 H), 5.02
1
3
(dd, J = 14.5, 1.8 Hz, 1 H), 5.35 (s, 1 H), 5.79 (ddt, J = 14.5, 9.0,
8
2
.0 Hz, 1 H) ppm. 13C NMR (50 MHz, CDCl
1.02, 39.59, 39.71, 42.51, 115.0, 127.0, 137.49, 145.87 ppm.
): δ = 30.75 ppm.
3
): δ = 13.87, 15.68,
1
1
B
126.20 (CHPh), 125.50 (2 CHPh), 33.60 (br., 2 CH B), 30.86 (br.,
2
1
1
NMR (64 MHz, CDCl
3
CH B), 17.77 (2 CH ), 17.35 (2 CH ) ppm. B NMR (64 MHz,
2
3
2
CDCl
3
): δ = 86.14 (s) ppm.
2-Phenyl-1,4-pentadiene (7a). Method A: An aqueous solution
NaOH (5 , 50 mL, 0.25 mol) was added with stirring to a solution
of 5a (12 g, 0.056 mol) in hexane (30 mL). The reaction mixture
was stirred at room temperature until complete deboronation
2,3-Diphenyl-1,4-pentadiene (13): Borane 8 (1 g, 5 mmol) at –15 °C
was added to a solution of BCl in hexane (0.8 , 6.4 mL,
3
5.1 mmol). The solution was stirred at 0 °C for 15 min. The mixture
was then cooled to –30 °C and a solution of phenylacetylene
(0.52 g, 5.1 mmol) in hexane (1 mL) was rapidly added through a
syringe. The reaction was allowed to warm to 0 °C for 1 h and
stirred for 30 min. The reaction was quenched by addition of
AcONa (melted) (1.64 g, 20 mmol) in AcOH (4 mL) and refluxed
(
negative green-flame test of organic layer). Then the organic layer
was separated and the aqueous layer was extracted with hexane
3×15 mL). The combined extracts were dried with K CO and the
solvents evaporated. Vacuum distillation of the residue gave 7a
(
2
3
1
(
5.8 g, 73%) as a colorless liquid, b.p. 101–102 °C (10 Torr).
NMR (200 MHz, CDCl ): δ = 7.3–7.50 (m, 5 H), 5.85–6.10 (m, 1
H), 5.44 (s, 2 H), 5.09–5.21 (m, 2 H), 3.30 (d, J = 6.5 Hz, 2 H) ppm.
H
3
for 1 h. The hexane layer was washed with water, NaHCO
3
(10%),
dried with Na SO and the solvents evaporated. Flash chromatog-
2
4
Eur. J. Org. Chem. 2005, 4633–4639
www.eurjoc.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4637

Y. N. Bubnov, N. Y. Kuznetsov, F. V. Pastukhov, V. V. Kublitsky
(CH=), 128.06 (2 CHPh), 127.06 (2 CHPh), 125.67 (CHPh), 115.66
FULL PAPER
raphy of the residue with hexane furnished diene 13 (0.76 g, 68%)
1
as a yellowish oil (R
f
= 0.21). H NMR (400 MHz, CDCl
3
): δ = (CH
2
=), 51.04 (2 CH
3
O), 43.00 (CH), 41.04 (CH
B) ppm. B NMR (64 MHz, CDCl ): δ = 31.03 [s,
R-B(OMe) ] ppm. MS (70 eV, EI): m/z (%) = 218 (Ͻ3) [M] , 131
(40), 105 (70), 91 (100), 79 (20), 77 (20), 67 (15), 58 (20), 41 (70).
(218.1): calcd. C 71.59, H 8.78, B 4.96; found C 71.61,
C), 140.25 (CH), 128.69 (2 CH), 128.41 (2 CH), 128.16 (2 CH), H 8.83, B 4.90.
2
), 21.05
1
1
7
1
4
.42 (m, 2 H), 7.33–7.20 (m, 8 H), 6.22 (ddd, J = 7.2, 10.2, 17.1 Hz, (br., CH
2
3
+
H), 5.60 (s, 1 H), 5.21 (dt, J = 10.2, 1.2 Hz, 1 H), 5.18 (s, 1 H),
2
.99 (dt, J = 17.1, 1.6 Hz, 1 H), 4.67 (d, J = 6.5 Hz, 1 H) ppm.[
18]
1
3
C NMR (100 MHz, CDCl
3
): δ = 149.78 (C), 141.61 (C), 141.54
13 2
C H19BO
(
1
2
27.32 (CH), 126.58 (2 CH), 126.46 (CH), 116.28 (CH =), 115.54
5
-Allyl-1-chloro-3-propyl-2-borinene (20): 1-Pentyne (7.4 mL,
+
(CH
2
=), 54.07 (CH) ppm. MS (70 eV, EI): m/z (%) = 220 (3) [M] ,
0.075 mol) was added to a solution of 1c (0.075 mol, prepared as
+
+
2
05 (4) [M – CH
3
] , 179 (15) [M – C
3
H
5
] , 129 (15), 117 (35), 115
16 (220.3):
indicated above) in hexane (25 mL) at –15 °C. The reaction mixture
was stirred for 1 h at 20 °C, and the solvent evaporated under re-
duced pressure. The residue was distilled in vacuo to give borane
(30), 105 (100), 91 (70), 77 (98), 51 (65), 43 (30). C17
H
calcd. C 92.68, H 7.32; found C 92.55, H 7.14.
1
2
-(2-Methylenecyclobutyl)-3-(trimethylsilyl)-1-propanol (15) and 3- 20 (12.5 g, 85%) as a colorless liquid, b.p. 64–65 °C (1 Torr). H
(1-Cyclobutenyl)-2-[(trimethylsilyl)methyl]-1-propanol (16): A mix-
NMR (300 MHz, CDCl ): δ = 0.88 (dd, J = 12.67, 3.0 Hz, 1 H),
0.94 (t, J = 7.4 Hz, 3 H), 1.54 (m, 2 H), 1.60 (dd, J = 12.67, 6.5 Hz,
3
[15]
ture of isomeric boranes 14a and 14b
(0.5 g, 3.0 mmol) was
added to a solution of BCl
The solution was stirred for 15 min at –15 to –5 °C and then the
reaction mixture was cooled to –15 °C and allyltrimethylsilane
3
(0.82 , 3.7 mL, 3.0 mmol) at –15 °C.
1 H), 1.19–2.25 (m, 2 H), 2.21 (m, 2 H), 2.21 (t, J = 7.54 Hz, 2 H),
2.95 (d, J = 13.5 Hz, 1 H), 5.01 (d, J = 2.9 Hz, 1 H), 5.05 (s, 1 H),
1
3
5.7–5.86 (m, 1 H), 5.92 (s, 1 H) ppm. C NMR (50 MHz, CDCl3):
δ = 13.69, 20.27, 29.96, 35.61, 39.13, 42.46, 42.99, 116.05, 127.38,
(
0.25 g, 0.35 mL, 2.2 mmol) was rapidly added. The reaction mix-
ture was kept for 20 h at –8 °C. After that, NaOH (3 , 6 mL,
8 mmol), THF (5 mL) and H
1
1
136.26, 177.03 ppm. B NMR (64 MHz, CDCl ): δ = 64.40
3
+
1
2
O
2
(30%, 3 mL) were added to the (s) ppm. MS (70 eV, EI): m/z (%) = 195 (7) [M – 1] , 182 (10) [M –
+
+
+
cooled reaction mixture, which was then stirred overnight at ambi-
ent temperature. The organic layer was separated, dried with
2 5
14] , 167 (25) [M – C H ] , 153 (20) [M – Pr] , 107 (46), 95 (53),
+
91 (69), 79 (78), 67 (100) [C H ] , 55 (25), 41 (33). C H BCl
5
7
11 18
Na
residue with n-C
of isomeric alcohols 15 and 16 (0.36 g, 82%) as a viscous oil (R
2
SO
4
and the solvent evaporated. Flash chromatography of the
(196.5): calcd. C 67.23, H 9.23, B 5.50; found C 66.47, H 9.76, B
4.97.
6
H14/EtOAc (9:1) on silica gel furnished a mixture
f
=
1
5-Allyl-1-isopropoxy-3-propyl-2-borinene (21): A mixture of isopro-
pyl alcohol (1.1 mL, 0.014 mol) and Et N (1.94 mL, 0.014 mol) was
3
added with rigorous stirring to a solution of 20 (2.8 g, 0.014 mol)
in hexane (40 mL) at –40 °C. The mixture was stirred for 2 h at
3
room temperature. A precipitate of Et NHCl was filtered off and
3
0.16) in a ratio of 1:2. H NMR (400 MHz, CDCl ) [the bolded
subscripts 15 and 16 show that the proton indicated belong to com-
pounds 15 and 16, respectively]: δ = 5.71 (s, 1 H16), 4.82 (q, J =
2
1
3
1
2
1
1
.4 Hz, 1 H15), 4.76 (q, J = 2.4 Hz, 1 H15), 3.65 (dd, J = 5.6,
0.4 Hz, 1 H15, CH OH), 3.53 (t, J = 5.6 Hz, 1 H15, CH OH),
.51 (t, J = 5.6 Hz, 1 H16, CH OH), 3.47 (dd, J = 6.4, 10.8 Hz,
16, CH OH), 3.07 (dtt, J = 6.5, 10.2, 2.6 Hz, 1 H15), 2.60–
.50 (m, 2 H), 2.42 (m, 2 H16), 2.34 (m, 2 H16), 2.10 (dd, J = 7.2,
6.4 Hz, 1 H16), 2.02–1.95 (m, 1 H16, 1 H15), 1.84 (sept, J = 6.0 Hz,
a
H
b
a b
H
washed with hexane (2×10 mL); the filtrate was evaporated under
reduced pressure. Distillation of the residue gave 21 (1.75 g, 57%)
a
H
b
H
a b
H
1
as a yellow liquid, b.p. 95–96 °C (2 Torr). H NMR (300 MHz,
CDCl
H), 1.28 (dd, J = 15.8, 6.3 Hz, 1 H), 1.23 (d, J = 6.8 Hz, 6 H),
1.47 (tq, J = 7.7, 7.3 Hz, 2 H), 1.83 (d, J = 12.2 Hz, 1 H), 1.70–
.90 (m, 1 H), 2.05–2.15 (m, 3 H), 2.12 (t, J = 7.7 Hz, 2 H), 4.47
sept, J = 6.8 Hz, 1 H), 4.94 (s, 1 H), 5.02 (d, J = 4.2 Hz, 1 H),
3
): δ = 0.50 (dd, J = 15.8, 11.6 Hz, 1 H), 0.90 (t, J = 7.3 Hz,
3
H16), 1.80–1.72 (m, 3 H), 0.59 (dd, J = 6.4, 0.8 Hz, 2 H15), 0.55
d, J = 6.8 Hz, 2 H16), 0.02 (s, 9 H15), 0.01 (s, 9 H16) ppm. 1
NMR (100 MHz, CDCl ): compound 15: δ = 149.22 (C15), 104.90
15), 65.63 (CH2,15), 47.95 (CH15), 35.53 (CH15), 28.97
CH2(cycle)15), 20.18 (CH2(cycle)15), 16.12 (CH Si15), –0.86 (3 CH3,15
3
(
C
1
3
(
5
2
(CH =
1
3
3
.53 (s, 1 H), 5.70–5.90 (m, 1 H) ppm. C NMR (50 MHz, CDCl ):
(
2
)
δ = 13.84, 20.76, 24.55, 25.00, 35.96, 39.77, 40.86, 43.28, 68.15,
ppm; compound 16: δ = 153.12 (C16), 128.73 (CH=16), 68.01
1
1
1
15.29, 125.68, 137.27, 170.66 ppm. B NMR (64 MHz, CDCl
3
):
(CH2,16), 39.45 (CH16), 35.83 (CH2,16), 31.76 (CH2(cycle)16), 26.69
+
δ = 46.16 (s, iPrOBϽ). MS (70 eV, EI): m/z (%) = 220 [M] , 191
(
CH2(cycle)16), 18.66 (CH
2
Si16), –0.68 (3 CH3,16) ppm. MS (70 eV,
+
+
+
+
(30) [M – C
109 (36), 94 (58), 91 (72), 79 (73), 67 (100) [C
37). C14 25BO (196.5): calcd. C 76.38, H 11.45, B 4.91; found C
6.47, H 11.44, B 4.88.
2 5
H ] , 179 (15), 177 (20), 161 (22), 150 (56), 121 (45),
EI): m/z (%) = 198 [M] , 197 [M – H] , 157 (40) [M – C
3
H
5
] , 147
+
+
5 7
H ] , 55 (40), 41
(
(
6
18), 129 (51) [M – H
50), 43 (80). C11 22OSi (198.4): calcd. C 66.60, H 11.18; found C
6.04, H 10.92.
2
O] , 83 (40), 75 (90), 73 (100), 59 (40), 55
(
7
H
H
Dimethyl 2-Phenyl-4-pentenylboronate (18): Styrene (4.06 g, 4.5 mL,
9 mmol) was added at –40 °C to a solution of allyl(dibromo)bo- Acknowledgments
rane 1b (78 mmol, prepared as described above) in hexane
100 mL). The mixture was allowed to warm to 0 °C and stirred at
this temperature for 2 h. Then a mixture of Et N (16.2 g, 22.3 mL,
3
(
This work was supported by the Russian Foundation for Basic Re-
search (grant no. 05.03.33268), the Russian Academy of Sciences
3
160 mmol) and MeOH (5.1 g, 6.5 mL, 160 mmol) was added at (Programme for 2003–2005), an R.F. President’s grant for the sup-
–
60 °C with rigorous stirring. When the mixture reached room tem-
port of leading scientific schools (grant no. NSh 1917.2003.3) and
the Division of Chemistry and Material Sciences of the R.A.S.
(Programme no. 1).
perature, a precipitate of Et
washed with hexane. The filtrate was evaporated under reduced
pressure and the residue was subjected to vacuum distillation,
3
NHBr was filtered off and thoroughly
which provided boronate 18 (6.2 g, 74%) as a colorless liquid, b.p.
[
1] a) D. S. Matteson, Stereodirected Synthesis with Organobor-
anes, Springer, Berlin, 1995; b) A. Pelter, K. Smith, H. C.
Brown, Borane reagents, Academic Press, London, 1988; c)
B. M. Mikhailov, Y. N. Bubnov, Organoboron compounds in or-
ganic synthesis, Harwood Academic Scientific Publishers, Lon-
don, New York, 1984.
1
8
5
9
0–84 °C (2 Torr). H NMR (400 MHz, CDCl
H), 5.74 (m, 1 H), 5.02 (d, J = 17.12 Hz, 1 H), 4.98 (d, J =
.96 Hz, 1 H), 3.51 (s, 6 H), 3.02 (m, 1 H), 2.44 (t, J = 7.16 Hz, 2
3
): δ = 7.35–7.19 (m,
H), 1.25 (dd, J = 7.48, 15.56 Hz, 1 H), 1.12 (dd, J = 7.48, 15.56 Hz,
1
H) ppm. 13C NMR (50 MHz, CDCl
3
): δ = 147.40 (CPh), 137.31
4638
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 4633–4639

Allylhaloboranes and the Allylboration of Alkenes and Acetylenes
FULL PAPER
[
2] a) Y. N. Bubnov, Pure Appl. Chem. 1987, 59, 895–906; b) Y. N.
Bubnov in Science of Synthesis Houben-Weyl Methods of
molecular Transformation (Eds.: D. E. Kaufmann, D. S.
Matteson), Georg Thieme Verlag, Stuttgart, 2005, vol. 6,
ch. 35, pp. 942–1072.
[10] a) D. A. Singleton, S. C. Waller, Z. Zhang, D. E. Frantz, S.-W.
Leung, J. Am. Chem. Soc. 1996, 118, 9986–9987; b) D. E.
Frantz, D. A. Singleton, Org. Lett. 1999, 1, 485–486.
[11] a) S. L. Serre, J.-C. Guillemin, Organometallics 1997, 16, 5844–
5848; b) K. M. Depew, S. J. Danishefsky, N. Rosen, L. Sepp-
Lorenzino, J. Am. Chem. Soc. 1996, 118, 12463–12464; c) J. M.
Sohkeryanz, J. C. G. Woo, P. Siliphaivanh, K. M. Depew, S. J.
Danishefsky, J. Am. Chem. Soc. 1999, 121, 11964–11975; d) Y.
Tanigawa, I. Moritani, S. Nishida, J. Organomet. Chem. 1971,
28, 73–79.
[
[
3] P. V. Ramachadran, Aldrichimica Acta 2002, 35, 23–35.
4] a) Y. N. Bubnov, M. S. Grigorian, A. V. TsybanЈ, B. M. Mi-
khailov, Synthesis 1980, 902–904; b) . Y. N. Bubnov, M. Y. Et-
inger, Tetrahedron Lett. 1985, 26, 2797–2800; c) Y. N. Bubnov,
L. I. Lavrinovich, Tetrahedron Lett. 1985, 26, 4551–4554; d)
Y. N. Bubnov, V. I. Zheludeva, Izv. Acad. Nauk SSSR, Ser.
Khim. 1987, 235–236; e) Y. N. Bubnov, L. I. Lavrinovich, Izv.
[12] P. Harston, J. L. Wardell, D. Marton, G. Tagliavini, P. Smith,
Inorg. Chim. Acta 1989, 162, 245–250.
Acad. Nauk SSSR, Ser. Khim. 1988, 420–425; f) Y. N. Bubnov, [13] R. W. Hoffmann, G. Feussner, H. J. Zeiss, S. Schulz, J. Or-
M. E. Gurskii, D. G. Pershin, Izv. Acad. Nauk SSSR, Ser.
Khim. 1987, 1193–1194; g) Y. N. Bubnov, V. I. Zheludeva, T. C.
Kuznetsova, Izv. Acad. Nauk SSSR, Ser. Khim. 1987, 2632–
ganomet. Chem. 1980, 187, 321–329.
[14] a) B. M. Mikhailov, Y. N. Bubnov, B. S. Bogdanov, Zh. Org.
Chim. 1975, 45, 324–332; b) B. M. Mikhailov, Y. N. Bubnov,
B. S. Bogdanov, Zh. Org. Chim. 1975, 45, 333–338 (Chem.
Abstr. 1975, 82, 111345d).
2633; h) Y. N. Bubnov, M. Y. Etinger, A. V. Ignatenko, Izv.
Acad. Nauk SSSR, Ser. Khim. 1989, 1343–1351; i) Y. N. Bub-
nov, V. I. Zheludeva, A. V. Ignatenko, Izv. Acad. Nauk SSSR,
Ser. Khim. 1989, 420–426; j) Y. N. Bubnov, V. I. Zheludeva,
A. V. Ignatenko, J. Organomet. Chem. 1989, 359, 151–158.
5] a) Y. N. Bubnov, O. A. Nesmeyanova, T. Y. Rudashevskaya,
B. M. Mikhailov, B. A. Kazansky, Tetrahedron Lett. 1971, 12,
[15] A mixture of dynamic isomers 14a and 14b was synthesized in
37% yield by metallation of methylenecyclobutane followed by
2
treatment with Pr BCl.
[
2153–2156; b) Y. N. Bubnov, B. A. Kazansky, O. A. Nesmey-
anova, T. Y. Rudashevskaya, B. M. Mikhailov, Izv. Acad. Nauk
SSSR, Ser. Khim. 1977, 2545 and references cited therein.
6] Y. N. Bubnov, A. V. Geiderich, A. V. Ignatenko, P. Y. Melesh-
kin, M. E. Gursii, Mendeleev Commun. 1994, 214–215.
[
[
[
[
a) Y. N. Bubnov, M. E. Gurskii, L. I. Lavrinovich, Izv. Akad.
Nauk SSSR, Ser. Khim. 1986, 1918–1919; b) I. D. Gridnev,
M. E. Gurskii, Y. N. Bubnov, Organometallics 1996, 15, 3696–
3702.
7] B. M. Mikhailov, Y. N. Bubnov, M. S. Grigorian, Zh. Obshch.
Khim. 1974, 44, 2465 and references cited therein.
8] Y. N. Bubnov, A. V. TsybanЈ, V. M. Mikhailov, Synthesis 1980,
[16] L. I. Zakharkin, V. I. Stanko, Izv. Acad. Nauk SSSR, Ser.
Khim. 1960, 1896–1898 (Chem. Abstr. 1961, 55, 15337d).
[17] a) K. Lee, J. Lee, P. H. Lee, J. Org. Chem. 2002, 67, 8265–8268;
b) Y. Naruta, Y. Nishigaichi, K. Maruyama, J. Org. Chem.
1991, 56, 2011–2017.
904–905.
9] a) B. Wrackmeyer, O. L. Tok, Y. N. Bubnov, Angew. Chem. Int.
Ed. 1999, 38, 124–126; b) B. Wrackmeyer, O. L. Tok, E. V.
Klimkina, Y. N. Bubnov, Inorg. Chim. Acta 2000, 300–302,
169–174; c) B. Wrackmeyer, M. H. Bhatti, S. Ali, O. L. Tok, [18] S. Araki, A. Imai, K. Shimizu, M. Yamada, A. Mori, Y. Butsu-
Y. N. Bubnov, J. Organomet. Chem. 2002, 657, 146–154; d) B.
Wrackmeyer, O. L. Tok, Y. N. Bubnov, Appl. Organomet.
Chem. 2004, 18, 43–50 and references cited therein.
gan, J. Org. Chem. 1995, 60, 1841–1847.
Received: June 1, 2005
Published Online: September 12, 2005
Eur. J. Org. Chem. 2005, 4633–4639
www.eurjoc.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4639