Boron-catalyzed CC functionalization of allyl alcohols

Article abstract of DOI:10.1002/adsc.201801389

Tris(pentafluorophenyl)borane-catalyzed CC bond functionalization of arylallyl alcohols using donor-acceptor carbenes is presented. The allylic hydroxyl group is found to assist the product formation by neighboring group participation providing a clue towards mechanistic understanding. This method can also be employed to effect homologation of allyl alcohols to homoallyl alcohols. Overall, this metal-free transformation presents a novel disconnection strategy towards carbon-carbon bond scission and formation.

Full text of DOI:10.1002/adsc.201801389

Title: Boron-Catalyzed C-C Functionalization of Allyl Alcohols
Authors: Santhosh Rao, Raja Kapanaiah, and Kandikere Prabhu
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201801389
Link to VoR: http://dx.doi.org/10.1002/adsc.201801389

10.1002/adsc.201801389
Advanced Synthesis & Catalysis
COMMUNICATION
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
Boron-Catalyzed C-C Functionalization of Allyl Alcohols
Santhosh Rao,a Raja Kapanaiah,a and Kandikere Ramaiah Prabhua,*
a
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, Karnataka, India.
E-mail: prabhu@iisc.ac.in
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please
delete if not appropriate))
Carbenes are one of the highly reactive
Abstract. Tris(pentafluorophenyl)borane-catalyzed C–C
bond functionalization of arylallyl alcohols using donor- intermediates. Their ability to insert between C-H and
heteroatom-H bonds is well documented.[18-24] In this
acceptor carbenes is presented. The allylic hydroxyl group
is found to assist the product formation by neighboring
group participation providing a clue towards mechanistic
understanding. This method can also be employed to effect
homologation of allyl alcohols to homoallyl alcohols.
Overall, this metal-free transformation presents a novel
disconnection strategy towards carbon–carbon bond
scission and formation.
respect, organic diazo reagents have had a profound
influence as the carbene precursors.[25] However, the
utility of these reagents is underrepresented in non-
transition metal catalysis. It was only recently that
activation of diazo compounds by boron was
reported.[26] In this regard, Tayama reported an
aniline para-substitution reaction with diazo esters.[27]
More recently, a seminal work by Zhang on B(C6F5)3
Keywords: tris(pentafluorophenyl)borane; diazo; carbene;
C-C functionalization; allyl alcohol
catalyzed
ortho-substitution
of
phenols
is
noteworthy.[28] Nonetheless, the full potential of
B(C6F5)3 with the diazo reagents still needs to be
realized. In continuation of our earlier work,[29] we
report β-(sp2)-carbon functionalization of cinnamyl
alcohol with diazo derived donor-acceptor carbenes
(Scheme 1).[30] To the best our knowledge, the
present work is the first report in this direction.
Carbon-carbon bond manipulation is the basis of
synthetic organic transformations. Unlike the widely
explored
C-H
and
C-heteroatom
bond
functionalization reactions, functionalizing C-C
bonds is a challenge to date. Hence, a straightforward
C-C bond functionalization by scission and formation
of a new C-C bond at the same carbon will be a
significant advancement. The development in this
regard will pave the way for new C-C disconnection
strategies for synthetic methodology development.
Owing to their ready modulation of steric and
electronic properties, boron centric compounds have
effectively transitioned from stoichiometric reagents
to excellent catalysts.[1] In this direction, B(C6F5)3 has
intrigued the scientific community since its
emergence.[2,3] Subsequent reports of its ability for
activating dihydrogen in the frustrated Lewis pair
(FLP) chemistry, in a reversible fashion, added an
extra dimension to its ability.[4-6] As part of FLP
chemistry, B(C6F5)3 has been explored to activate a
range of small molecules such as carbon oxides,
Scheme 1. B(C6F5)3 Catalyzed C-C Functionalization.
nitrogen
oxides,
and
sulfur
oxides.[7]
Tris(pentafluorophenyl)borane has also been used as
an excellent activator for metallocene Ziegler-Natta
catalysts.[8] With its high acidity and steric bulk,
B(C6F5)3 has been an efficient Lewis acid catalyst,[9-
We initiated the optimization using cinnamyl
alcohol (1a) and methyl phenyldiazoacetate (2b) as
model substrates (Table 1). A bulky and strong Lewis
acid, B(C6F5)3 was chosen as the catalyst. After a few
initial controls, we were pleased to observe the
desired product 3ab in 26% yield (entry 1).
Alongside, commonly observed O-H insertion side
12]
especially towards C-C bond formation.[13-15]
Recently, it was also found by Szymczak[16] and
Simonneau[17] that B(C6F5)3 can interact with N2
containing transition complexes.
1
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10.1002/adsc.201801389
Advanced Synthesis & Catalysis
products of diazo carbene to cinnamyl alcohol (4) and
water (5) were detected as well. Extended solvent
controls revealed DCM as the suitable solvent for this
transformation (entries 2-7). Cinnamyl alcohol failed
to react in CH3CN and THF solvents presumably due
to the deactivation of the catalyst (entries 6 and 7).
Changing the catalyst to BF3.Et2O, a better Lewis
acid catalyst but devoid of the steric bulk, did not
afford any product (entry 8). This experiment
products with 1a resulted in the reduction of the
product yield. This was significant in reactions with
higher catalyst concentration. However, we were able
to circumvent this to a considerable extent by
employing lower catalyst loading and carrying out the
reaction in higher dilution. Hence, the reaction yield
improved significantly by increasing the solvent
volume to 8 mL (63%, entry 15). Even after extensive
optimization studies, the formation of 4 and 5 was
found to be inevitable. Nevertheless, we were pleased
to observe the desired product 3aa in good yields.
Following the optimization, substrate scope was
studied by reacting cinnamyl alcohol with a variety of
α-aryl-α-diazoacetates (Table 2). Similar to the
substrate 2a, diazo compounds with different ester
functionalities viz. methyl (2b), 2-butyl (2c),
trichloroethyl (2d), and benzyl (2e) reacted well to
give the corresponding products 3aa-ae in moderate
to good yields. Diazo compound that has an alkyl
substituent on the donor-aromatic ring (2f) did not
affect the reaction and reacted well to furnish the
corresponding product 3af. Diazo compounds having
an electron-donating group such as ortho-methoxy or
an electron-withdrawing group such as para-fluro
reacted well furnishing the products 3ag and 3ah in
moderate yields. Many halo substituted diazo
compounds containing fluoro, chloro, bromo or iodo,
and tosyl group were successfully tested. Halide
substitution on the aromatic ring did not affect the
overall yield of the expected product (3ah-an).
However, the tosyl group reduced the yield of 3ao
considerably (21%). Nonetheless, these substituents
can be beneficial in the late stage functionalization of
the obtained products.
The scope of the reaction was examined by treating
a variety of cinnamyl alcohol derivatives with methyl
2-diazo-2-(2-iodophenyl)acetate 2p (Table 3).
Cinnamyl alcohol reacted smoothly with 2p affording
the product 3ap in good yield (60%). To probe its
electronic (para-position) and steric (ortho-position)
effect on the reaction, reaction of diazo compound 2p
with cinnamyl alcohol having alkyl substitution on
the aromatic ring was carried out, which resulted in
comparable yields (3bp and 3cp). Cinnamyl alcohol
derivative possessing an ether functionality on the
aromatic ring also reacted well to provide the desired
product 3dp in 51% yield. However, the reaction of
1p with cinnamyl alcohol having electron-
withdrawing groups such as –NO2 and –CF3 on the
aromatic moiety resulted in a marginal reduction in
the yields of the desired products 3ep and 3fp,
respectively. The isolation of 3ep proved to be
difficult due to its instability on the silica column
during the chromatographic purification. Different
cinnamyl alcohol substrates comprising halo
substituents such as fluoro, chloro and bromo groups
on the aromatic ring furnished the corresponding
products 3gp-3kp in moderate to good yields. In
these reactions, both ortho- and para-substituted
suggested
that
bulky
electron
deficient
tris(pentafluorophenyl) ring is required for the
reaction to proceed. Employing a different Lewis acid
i.e., TMSOTf as the catalyst also supported the same
conclusion as this reaction also did not furnish the
desired product 3ab (entry 9). Screening of the
amount of catalyst loading suggested that 2.5 mol %
of the catalyst is optimum for the reaction (entry 10).
Table 1. Reaction Optimization[a]
entry catalyst (mol %)
solvent
yield[b]
3
4
5
used methyl phenyldiazoacetate (2b) as the diazo compound
1
B(C6F5)3 (5)
B(C6F5)3 (5)
B(C6F5)3 (5)
B(C6F5)3 (5)
B(C6F5)3 (5)
B(C6F5)3 (5)
B(C6F5)3 (5)
BF3.Et2O (5)
TMSOTf (5)
B(C6F5)3 (2.5)
Et2O
26
40
36
36
27
21
37
50
35
51
28
2
DCM
DCE
23
3
27
4
CHCl3
toluene
CH3CN
THF
25
5
29
no reaction
no reaction
nd
6
7
8
DCM
DCM
DCM
nd
nd
42
nd
25
39
9
nd
10
24
used isopropyl phenyldiazoacetate (2a) as the diazo compound
11
12
13
14
15c
B(C6F5)3 (2.5)
DCM
DCM
DCM
DCM
DCM
52
25
38
B(C6F5)(OH)2 (5)
B(C6F5)3/PPh3 (2.5)
B(C6F5)3/PCy3 (2.5)
B(C6F5)3 (2.5)
no reaction
22
17
20
28
49
65
35
12
63 (52)
[a]
Reaction conditions: 1a (0.2 mmol), 2 (0.4 mmol),
solvent (3 mL), rt, 12 h.
[b]
1
Measured by H NMR with terephthalaldehyde as the
internal standard, nd = not detected. The numbers in
parentheses are isolated yields.
[c] solvent (8mL).
After
a
few initial controls, isopropyl
phenyldiazoacetate (2a) was found to be a better
diazo reagent which furnished an improved yield of
the product 3aa (52%, entry 11). Replacing B(C6F5)3
with B(C6F5)(OH)2, one of possible catalyst
decomposition products, did not afford the expected
product (entry 12). The inclusion of a Lewis basic
phosphine such as PPh3 (triaryl) or PCy3 (trialkyl)
along with B(C6F5)3 in the reaction was not helpful in
enhancing the desired product yield (entries 13 and
14). In all the cases, competitive O-H insertion side
2
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10.1002/adsc.201801389
Advanced Synthesis & Catalysis
Table 2. Scope of the α-Aryl-α-diazoacetates
cinnamyl alcohols resulted in the formation of the
products in comparable yields ruling out the steric
effects on the product formation. An aldehyde
functionality on cinnamyl alcohol (1l) resulted in the
formation of the product 3lp, the isolation of this
product was unsuccessful due to the similar Rf with
O-H insertion impurities.
Following the substrate scope, the utility of the
present reaction was studied (Scheme 2). The
reaction was reproducible even when the scale was
increased tenfold (2 mmol, 56% yield). The C-C
functionalized product 3ap was further reduced using
LiAlH4 to obtain homoallyl alcohol 3ap’. Here, as
expected, the iodo functionality underwent reduction
furnishing the product 3ap’.[31] This is a promising
homologation method to obtain homoallyl alcohols
from allyl alcohols, which otherwise may require
cumbersome multistep synthetic protocols.[32]
Reaction conditions: 1a (0.2 mmol), 2 (0.4 mmol), DCM
(8 mL). 1H NMR yield was determined using
terephthalaldehyde as the internal standard.
Scheme 2. Synthetic Utility.
A preliminary mechanistic investigation was
carried out to follow the reaction pathway (Scheme 3).
Our approach involved either to verify or rule out the
potential substrate and catalytic intermediates.
Reacting cinnamyl alcohol (1a) in the absence of the
diazo compound (2b) resulted in no reaction
indicating 1a is not converted to any other
intermediate before reacting with 2b.
Table 3. Scope of the Allyl Alcohols
Further, it was necessary to rule out any in-situ
oxidized products of 1a that can act as the active
substrates for the present reaction. Hence, we
employed cinnamaldehyde (6a) and cinnamic acid
(7a) as the substrate instead of cinnamyl alcohol in
two separate controls. Cinnamaldehyde underwent a
complete conversion to a complex reaction mixture
comprising mainly diazo derived dimer and water O-
H insertion products. The expected product 3ab was
not observed at all. Cinnamic acid also underwent
complete conversion to corresponding O-H insertion
product (7ab, 83%) and the desired product 3ab was
not found.
Next, α-vinylbenzyl alcohol (8a) was used instead
of cinnamyl alcohol 1a. In this reaction, 8a reacted in
a similar fashion to cinnamyl alcohol 1a providing
the corresponding product 3ab. This reaction
suggests that the reaction of both cinnamyl alcohol
and α-vinylbenzyl alcohol with diazo compound 2b is
proceeding via a similar intermediate. Additionally,
we also subjected α-vinylbenzyl alcohol to the
Reaction conditions: 1 (0.2 mmol), 2p (0.4 mmol), DCM
(8 mL). 1H NMR yield was determined using
terephthalaldehyde as the internal standard. [a] 3ep
decomposed on silica during purification. [b] 3lp could not
be purified by chromatography.
3
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10.1002/adsc.201801389
Advanced Synthesis & Catalysis
B(C6F5)3 conditions to probe if it can isomerize to the
more stable cinnamyl alcohol (1a).[33] This reaction
showed that the catalyst can indeed isomerize 8a to
1a. However, considering the high reactivity of the
diazo compounds, we believe that the isomerization
can occur simultaneously along with the nucleophilic
attack on to the carbene center.
Substituting the nucleophilic carbon in the α-
vinylbenzyl alcohol with an electron withdrawing
group such –CO2Me (9a) resulted in no reaction with
almost all the starting allyl alcohol being intact in the
reaction mixture. Further, using homoallyl alcohol
(10a) in the place of 1a resulted in partial dehydration
to give a diene 10ab as the sole alcohol derived
product in a complex reaction mixture comprising O-
H insertion side products. These controls suggested
the necessity of sufficient nucleophilic character of
the β-sp2-carbon of cinnamyl alcohol (or α-
vinylbenzyl alcohol) and an active role of the
aromatic ring in stabilizing the incipient-cation that
may be generated during the reaction.
Role of the hydroxyl group also was investigated
by using cinnamyl methyl ether (11a) as the substrate.
This reaction failed to yield any product, and almost
all of 11a remained unreacted.
We also tried to understand the role of the aromatic
ring in the product formation. Here, instead of
cinnamyl alcohol, (E)-3-cyclohexylprop-2-en-1-ol
(12a) was employed under the standard conditions.
However, the reaction failed to provide the desired C-
C functionalized product but only a trace quantity of
the allyl alcohol derived O-H insertion product was
observed in the crude 1H NMR.
A secondary alcohol (E)-4-phenylbut-3-en-2-ol
(13a) instead of cinnamyl alcohol (1a) also failed to
provide the desired product. Instead only a trace
quantity of the O-H insertion product was observed.
Proceeding further, the presence of any active
catalytic intermediates derived from the B(C6F5)3 was
investigated. Hence, we used different reagents which
can act as hydride sources such as pinacolborane and
triethylsilane. Both these controls resulted in the
decreasing of the desired product yield, and did not
have any lasting effect on the reaction outcome. This
effectively ruled out the presence of a catalytic
intermediate [H-B(C6F5)3]-, in the reaction medium.
Accordingly,
based
and
on
our
the
literature
experimental
precedence[15,26,28,34]
observations, we have proposed a mechanism in
Scheme 4. The boron reagent, B(C6F5)3 is known to
activate diazo compound (I) and thus can generate
carbene intermediate which is stabilized by the strong
Lewis acidic boron center of B(C6F5)3 (II).[34a] The
intermediate II may be stabilized by the resonance
due to the presence of the donor aryl group as well
the extended conjugation that can be possible with
the ester functionality. This carbenic center, devoid of
an octet, can react with the available nucleophiles. In
the presence of cinnamyl alcohol, hydroxyl (resulting
in O-H insertion side product 4) and allylic β-sp2-
carbon (resulting in the desired product 3) compete
with each other.
Scheme 3. Preliminary Mechanistic Controls.
4
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10.1002/adsc.201801389
Advanced Synthesis & Catalysis
Allylic β-sp2-carbon of cinnamyl alcohol can form
additional 12h at room temperature. After the completion
of the reaction (confirmed by TLC), the reaction mixture
was transferred to a separating funnel. Dichloromethane
(40 mL), water (30 mL) and 2 ml of aq. NH3 solution was
then added and the DCM was separated. DCM layer was
further washed once with brine solution (30 mL). The
organic layer was then dried over Na2SO4, filtered and
concentrated under vacuum. The resultant crude mixture
a C-C bond by reacting with the carbene complex II,
generating a benzylic cation (III). This cation can
further be stabilized by the neighboring oxygen atom
to generate IV leading to V containing an oxetane
system. Ring opening of V results in the desired
product 3 and the catalyst B(C6F5)3 is regenerated as
part of the catalytic cycle. Here, our attempts to
detect or trap formaldehyde, a plausible byproduct in
the reaction, failed. The efforts included employing
dimedone, a known reagent to determine the presence
of formaldehyde by way of forming formaldomedone
(dimedone-formaldehyde adduct) in a system (see
Supporting Information for the experimental
procedures).[35]
1
was analyzed using H NMR (using terephthalaldehyde as
the internal standard) to determine the NMR yield, and
purified on a silica gel column to afford 3ab in 52% (29
mg) yield.
Acknowledgements
This work was supported by SERB (EMR/2016/006358),
New-Delhi, CSIR (No. 02(0226)15/EMR-II), New-Delhi, Indian
Institute of Science, and R. L. Fine Chem. We thank Dr. A. R.
Ramesha (R. L. Fine Chem) for useful discussion. SR thanks
UGC for a fellowship.
References
[1] L. Deloux, M. Srebnik, Chem. Rev. 1993, 93, 763–784.
[2] A. G. Massey, A. J. Park, F. G. A. Stone, Proc. Chem.
Soc. 1963, 212.
[3]A. G. Massey, A. J. Park, J. Organomet. Chem. 1964, 2,
245–250.
[4] G. C. Welch, R. R. S. Juan, J. D. Masuda, D. W.
Stephan, Science 2006, 314, 1124–1126.
[5] D. W.; Stephan, G. Erker, Angew. Chem. Int. Ed. 2009,
49, 46–76.
[6] M. Oestreich, J. Hermeke, J. Mohr, Chem. Soc. Rev.
2015, 44, 2202–2220.
[7] D. W. Stephan, G. Erker, Chem. Sci. 2014, 5, 2625–
2641.
[8] X. Yang, C. L. Stern, T. Marks, J. J. Am. Chem. Soc.
1991, 113, 3623–3625.
[9] W. E. Piers, T. Chivers, Chem. Soc. Rev. 1997, 26,
345–354.
[10] G. Erker, Dalton Trans. 2005, 1883–1890.
[11] J. R. Lawson, R. L. Melen, Inorg. Chem. 2017, 56,
8627–8643.
[12] D. W. Stephan, G. Erker, Angew. Chem. Int. Ed. 2015,
54, 6400–6441.
[13] M. M. Hansmann, R. L. Melen, M. Rudolph, F.
Rominger, H. Wadepohl, D. W. Stephan, A. S. K.
Hashmi, J. Am. Chem. Soc. 2015, 137, 15469–15477.
[14] F. Ge, G. Kehr, C. G. Daniliuc, G. Erker, J. Am.
Chem. Soc. 2014, 136, 68–71.
Scheme 4. Proposed Mechanism.
In summary, we have developed a novel metal-free
disconnection approach to functionalize arylallyl
alcohols via C-C bond scission. Allylic hydroxyl
functionality was found to be important in stabilizing
the incipient carbocation formed during the reaction
providing
a
clue towards the mechanistic
understanding. The method has also been employed
to obtain homoallyl alcohols from allyl alcohols.
Hence, we believe that this approach can be a
stepping stone towards future methods to
functionalize C-C bonds.
[15] B. Rao, R. Kinjo, Chem. – Asian J. 2018, 13, 1279–
1292.
[16] J. B. Geri, J. P. Shanahan, N. K. Szymczak, J. Am.
Chem. Soc. 2017, 139, 5952–5956.
Experimental Section
[17] A. Simonneau, R. Turrel, L. Vendier, M. Etienne,
Angew. Chem. Int. Ed. 2017, 56, 12268–12272.
[18] M. P. Doyle, R. Duffy, M. Ratnikov, L. Zhou, Chem.
Rev. 2009, 110, 704–724.
[19] H. Keipour, V. Carreras, T. Ollevier, Org. & Biomol.
Chem. 2017, 15, 5441–5456.
[20] D. Gillingham, N. Fei, Chem. Soc. Rev. 2013, 42,
4918–4931.
[21] H. M. L. Davies, D. Morton, Chem. Soc. Rev. 2011,
40, 1857–1869.
Representative experimental procedure for the
B(C6F5)3-catalyzed C-C functionalization reaction: To a
pre-dried 25 mL round bottomed flask charged with a
magnetic stir bar, was weighed cinnamyl alcohol (1a, 0.2
mmol, 26.8 mg) and dissolved in dichloromethane (4 mL).
In another pre-dried vial was weighed diazo compound (2a,
0.4 mmol, 81.7 mg), dissolved in dichloromethane (4 mL)
and transferred to the round bottom flask containing the
cinnamyl alcohol substrate under nitrogen atmosphere
using Schlenk technique. B(C6F5)3 (2.5 mol %, 2.6 mg)
was weighed, transferred to the reaction mixture with
continuous stirring and the reaction mixture was sealed
using a rubber septum. Stirring was continued for an
5
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10.1002/adsc.201801389
Advanced Synthesis & Catalysis
[22] M. M. Díaz-Requejo, P. J. Pérez, Chem. Rev. 2008,
108, 3379–3394.
[30] H. M. L. Davies, J. R. Denton, Chem. Soc. Rev. 2009,
38, 3061–3071.
[23] X. Guo, W. Hu, Acc. Chem. Res. 2013, 46, 2427–
2440.
[31] G. J. Karabatsos, R. L. Shone, J. Org. Chem. 1968,
33, 619–621.
[24] S.-F. Zhu, Q.-L. Zhou, Acc. Chem. Res. 2012, 45,
1365–1377.
[32] Z. Li, M. K. Gupta, T. S. Snowden, Eur. J. Org.
Chem. 2015, 2015, 7009–7019.
[25] a) A. Ford, H. Miel, A. Ring, C. N. Slattery, A. R.
Maguire, M. A. McKervey, Chem. Rev. 2015, 115,
9981–10080; b) Y. Xia, D. Qiu, J. Wang, Chem. Rev.
2017, 117, 13810–13889; c) Q. Xiao, Y. Zhang, J.
Wang, Acc. Chem. Res. 2013, 46, 236–247; d) Z.
Zhang, J. Wang, Tetrahedron 2008, 64, 6577-6605.
[26] H. Li, Y. Zhang, J. Wang, Synthesis 2013, 45, 3090-
3098.
[27] E. Tayama, M. Ishikawa, H. Iwamoto, E. Hasegawa,
Tetrahedron Lett. 2012, 53, 5159–5161.
[28] Z. Yu, Y. Li, J. Shi, B. Ma, L. Liu, J. Zhang, Angew.
Chem. Int. Ed. 2016, 55, 14807–14811.
[33] E. A. Braude; P. H. Gore, Nature, 1954, 173, 1091–
1092.
[34] a) C. N. Tang, Q. M. Liang, A. R. Jupp, T. C.
Johnstone, R. C. Neu, D. T. Song, S. Grimme and D. W.
Stephan, Angew. Chem. Int. Ed., 2017, 56, 16588–
16592; b) P. A. Chase and D. W. Stephan, Angew.
Chem. Int. Ed., 2008, 47, 7433–7437; c) D.
Holschumacher, T. Bannenberg, C. G. Hrib, P. G.
Jones and M. Tamm, Angew. Chem. Int. Ed., 2008, 47,
7428–7432; d) Y. Hoshimoto, T. Kinoshita, M. Ohashi
and S. Ogoshi, Angew.Chem. Int.Ed., 2015, 54,11666–
11671.
[29] a) S. Rao, K. R. Prabhu, Org. Lett. 2017, 19, 846–
849; b) Boron-Catalyzed Carbonate Functionality
Transfer Reaction, submitted to the Asian J. Org. Chem
(submission number is ajoc.201800751).
[35] a) D. Spencer, T. Henshall, J. Am. Chem. Soc. 1955,
77, 1943-1948; b)
6
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Advanced Synthesis & Catalysis
COMMUNICATION
Boron-Catalyzed C-C Functionalization of Allyl
Alcohols
Adv. Synth. Catal. Year, Volume, Page – Page
Santhosh Rao, Raja Kapanaiah, and Kandikere
Ramaiah Prabhu *
7
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