Selective oxidation of benzylic, allylic and propargylic alcohols using dirhodium(II) tetraamidinate as catalyst and aqueous tert-butyl hydroperoxide as oxidant

Article abstract of DOI:10.1002/aoc.3281

We show that the dirhodium(II) tetraamidinate complex Rh₂(Msip)₄ efficiently catalyzes the oxidation of activated secondary alcohols at only 0.1 mol% loading. In this approach, we oxidized various benzylic, allylic and propargylic alcohols to the corresponding carbonyl compounds under mild aqueous conditions using the inexpensive oxidant T-HYDRO (70 wt% aqueous tert-butyl hydroperoxide).

Full text of DOI:10.1002/aoc.3281

Full Paper
Received: 27 August 2014
Revised: 19 December 2014
Accepted: 2 January 2015
Published online in Wiley Online Library: 16 February 2015
(wileyonlinelibrary.com) DOI 10.1002/aoc.3281
Selective oxidation of benzylic, allylic and
propargylic alcohols using dirhodium(II)
tetraamidinate as catalyst and aqueous
tert-butyl hydroperoxide as oxidant
Abudureheman Wusimana* and Chong-Dao Lub*
We show that the dirhodium(II) tetraamidinate complex Rh2(Msip)4 efficiently catalyzes the oxidation of activated secondary al-
cohols at only 0.1 mol% loading. In this approach, we oxidized various benzylic, allylic and propargylic alcohols to the correspond-
ing carbonyl compounds under mild aqueous conditions using the inexpensive oxidant T-HYDRO® (70 wt% aqueous tert-butyl
hydroperoxide). Copyright © 2015 John Wiley & Sons, Ltd.
Additional supporting information may be found in the online version of this article at the publisher’s web-site.
Keywords: dirhodium(II); catalyst; oxidation; alcohols; tert-butyl hydroperoxide
optimize reaction conditions. Initially reactions were performed at
room temperature using 1.0 mol% dirhodium(II) complexes and
Introduction
Selective oxidation of alcohols to the corresponding carbonyls is one of
the most fundamental reactions in organic synthesis,[1] and hence a
broad range of methods have been developed, including Swern
oxidation,[2] Dess–Martin oxidation[3] and oxidation in the presence of
various metal reagents.[4] Researchers have sought to replace the
oxidizing reagents in these methods with ecologically friendly and safe
catalytic systems based on such reagents as molecular oxygen, aqueous
hydrogen peroxide and tert-butyl hydroperoxide (TBHP).[5] TBHP has
been used as an alternative oxygen source[6] for alcohol oxidation cata-
lyzed by transition metals such as V,[7] Cr,[8] Mn,[9] Fe,[10] Co,[11] Cu,[12]
Zr,[13] Mo,[14] Ru,[15] Rh[16] and Au[17] among others.[18] These methods
have various disadvantages, including high catalyst loading, harsh
2.0 equiv. of T-HYDRO in various solvents (Table 1, entries 1–11).
Rh2(Msip)4 shows higher catalytic activity in water (Table 1, entry
2). Conducting the same reaction in DCM with anhydrous TBHP
gives much lower yield of product 1-(4-nitrophenyl)ethanone (2a)
(Table 1, entry 5). This suggests that water is an important determi-
nant of catalytic activity.[21] Closer inspection of aqueous oxidation
reactions reveals that the substrate 1a and dirhodium catalysts
show poor solubility. Therefore we switched to a biphasic system
and were pleased to obtain >95% yield of 2a in a mixed solvent
of DCM–H2O (1:9, v:v) (Table 1, entry 10). Decreasing the catalyst
loading to 0.1 mol% under the same reaction conditions reduces
the yield to 42%. Using 4.0 or 5.0 equiv. of T-HYDRO increases the
respective yield of 2a to 58 or 61% (Table 1, entries 12–14). Given
the potential usefulness of base in alcohol oxidations,[22] we tested
the effect of adding various bases on the yield of desired product.
While 50 mol% NaHCO3 increases the yield somewhat (Table 1,
entry 15), other bases tested (KOH, Na2CO3, K2CO3, (NH4)2CO3 and
NaOAc) either do not improve yield or they reduce it under the
same reaction conditions (Table 1, entries 16–20). The best result
of 95% yield is obtained using 3.0 equiv. of T-HYDRO and raising
the temperature to 40°C (Table 1, entry 24). Reducing the catalyst
[8d, 19]
conditions, poor selectivity and/or tedious workup procedures.
This highlights the need to identify better catalyst systems.
We recently reported the synthesis of dirhodium(II) tetraamidinate
derivative complexes Rh2(sip)4 (Fig. 1) and demonstrated that they
can be used to catalyze benzylic oxidation.[20] This success prompted
us to investigate whether the Rh2(sip)4/T-HYDRO system
(where T-HYDRO is 70 wt% aqueous TBHP) can efficiently and
selectively oxidize alcohols. We are aware of only one previous
report of dirhodium-catalyzed selective oxidation of alcohols. In
that study, Moody and Palmer[16b] used 1.0 mol% Rh2(OAc)4 as
catalyst and anhydrous TBHP in dichloromethane (DCM) to oxidize
benzylic and allylic alcohols. They found that prolonged reaction
times were required to achieve low to moderate yields. Here we
describe a milder and more efficient approach to achieve regio- and
chemoselective alcohol oxidation using only 0.1 mol% dirhodium(II)
tetraamidinate as catalyst and T-HYDRO in aqueous solution.
*
*
Correspondence to: Abudureheman Wusiman, School of Chemistry and Chemical
Engineering, Xinjiang Normal University, Urumqi 830054, People’s Republic of
China. E-mail: arahman@xjnu.edu.cn
Chong-Dao Lu, Xinjiang Technical Institute of Physics & Chemistry, Chinese
Academy of Sciences, Urumqi 830011, People’s Republic of China. E-mail:
clu@ms.xjb.ac.cn
a School of Chemistry and Chemical Engineering, Xinjiang Normal University,
Urumqi 830054, People’s Republic of China
Results and Discussion
First we used 1-(4-nitrophenyl)ethanol (1a) as a model substrate to
screen various dirhodium(II) complexes for catalytic activity and to
b Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences,
Urumqi 830011, People’s Republic of China
Appl. Organometal. Chem. 2015, 29, 254–258
Copyright © 2015 John Wiley & Sons, Ltd.

Dirhodium(II)-catalyzed selective oxidation of activated alcohols
electron-withdrawing or electron-donating groups in the aromatic ring
also react well (Table 2, entries 1–7). The desired 1-indanone (2h) is ob-
tained from the oxidation of 1-indanole (1h), and 3-(tert-butylperoxy)-
1-indanone is also isolated as a side-product in low yield (Table 2,
entry 8).[23] In contrast, the starting materials 1i and 1j, which are
derived from pyridinyl alcohols, show lower reactivity and give
yields of only 40 or 48% (Table 2, entries 9 and 10). This probably
reflects the fact that pyridinyl alcohols prefer to coordinate axi-
ally with the dirhodium species,[24] which impairs catalytic activ-
ity. A secondary aliphatic alcohol shows no detectable reaction
(Table 2, entry 11). Applying this protocol to the oxidation of pri-
mary benzylic alcohols generates the corresponding benzalde-
hyde and benzoic acid derivatives with poor selectivity (Table 2,
entries 12–16). Interestingly, alcohols with electron-withdrawing
substituents provide the corresponding aldehydes in higher yield
than acids. Nevertheless, we do not discern any general rules that
might allow us to predict the major products from a given
Figure 1. Dirhodium(II) tetraamidinate complexes, Rh2(sip)4.
loading to 0.05 mol% leads to 83% yield (Table 1, entry 26). No re-
action occurs in the absence of catalyst or T-HYDRO (Table 1,
entries 27 and 28).
Next, we applied the optimized reaction conditions using 0.1 mol
% Rh2(Msip)4 as catalyst (Table 1, entry 24) to investigate the scope
of catalytic alcohol oxidation (Table 2). Oxidation of secondary
benzylic alcohols proceeds smoothly and produces the corre-
sponding keto derivatives in excellent yield. Substrates with
Table 1. Optimization of reaction conditionsa
Entry
Catalyst
x (mol%)
T-HYDRO (equiv.)
Solventb
Base (50 mol%)
Temp. (°C)
Yield (%)c
1
Rh2(OAc)4
Rh2(Msip)4
Rh2(Tsip)4
Rh2(PMPsip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
Rh2(Msip)4
None
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.05
0.1
—
2.0
2.0
2.0
2.0
2.0d
2.0
2.0
2.0
2.0
2.0
2.0
2.0
4.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
4.0
3.0
2.0
5.0
0.0
5.0
H2O
H2O
H2O
H2O
DCM
DCM
—
—
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
Room temp.
40
4.5
77
2
3
—
63
4
—
65
5
—
22
6
—
36
7
DCM–H2O (1:1)
DCM–H2O (1:3)
DCM–H2O (1:6)
DCM–H2O (1:9)
MeOH–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
DCM–H2O (1:9)
—
56
8
—
70
9
—
84
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
—
>95
50
—
—
42
—
58
—
61
NaHCO3
Na2CO3
NaOAc
KOH
69
63
52
40
K2CO3
(NH4)2CO3
—
7
48
78
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
40
>95
>95
95
74
40
40
40
40
83
40
NRe
NRe
40
aReactions were performed with 1.0 equiv. (0.3mmol) of substrate and 70 wt% T-HYDRO in a sealed tube for 24 h, unless otherwise noted.
bThe ratio of the mixed solvent (v/v) is reported in parentheses.
cYield was determined by 1H NMR analysis of the crude reaction mixture.
dAnhydrous tert-butyl hydroperoxide (TBHP in decane) was used.
eNo reaction.
Appl. Organometal. Chem. 2015, 29, 254–258
Copyright © 2015 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

A. Wusiman and C.-D. Lu
Table 2. Rh2(Msip)4-catalyzed benzylic alcohol oxidationa
2t in respective isolated yields of 62 and 69% (Table 3, entries
1 and 3). In contrast, trans-1,3-diphenylprop-2-en-1-ol (1s) is
oxidized to trans-chalcone (2s) and 3-phenyl-2-benzoyl-oxirane
in isolated yields of 50 and 21% (Table 3, entry 2).
Finally, we assessed whether our optimized reaction conditions
would allow the chemoselective oxidation of various diols contain-
ing two hydroxyl groups, including one at the benzylic position.
Oxidation of 1-phenylethane-1,2-diol (4a) and 1-phenylpentane-
1,5-diol (4b) generates ketoalcohol derivatives in lower isolated
yields of 23 and 43%, respectively (Table 4, entries 1 and 2).
1-Phenylpropane-1,2-diol (4c) is oxidized to 2-hydroxy-1-
phenylpropan-1-one (5c) in 85% isolated yield (Table 4, entry
3). 1-Phenylpentane-1,3-diol (4d) is oxidized to β-ketoalcohol
5d in 75% isolated yield and to the β-ketoenol and β-diketo
derivatives 6d and 6d′ in 8% isolated yield in a 6:1 ratio.
These steps are depicted in Scheme 1. Applying this proce-
dure to androst-4-ene-3,17-diol (4e) leads to selective oxida-
tion of the allylic hydroxyl group, affording testosterone (5e)
in 78% isolated yield (Scheme 2).
To explore further the chemoselectivity of this method, we
carried out the oxidation reactions with a aliphatic alcohol (1K)
together with a mixture of benzylic, allylic or propargylic alcohols
under the given conditions. Only activated alcohols such as
1-(4-nitrophenyl)ethanol (1a), 1,3-diphenylprop-2-en-1-ol (1s)
and 1-phenylpent-1-yn-3-ol (1u) are oxidized to the correspond-
ing ketone, and no trace of oxidation of the aliphatic alcohol is
observed (Table 5).
Rh2(Msip)4-catalyzed alcohol oxidation most likely involves a free
radical mechanism that has been well documented in the Rh2
(cap)4-catalyzed protocol.[21,25] Consistent with the presence of a
one-electron oxidized dirhodium core (Rh52+), addition of TBHP
causes the Rh2(Msip)4 solution to change from light blue to pink
red and a low-energy absorption peak to appear at 969 nm in the
UV–visible spectrum.[20] In addition, preliminary results suggest that
adding a radical scavenger such as 2,6-bis(1,1-dimethylethyl)-4-
methylphenol inhibits the oxidation of substrate 1a.[26] Therefore
we propose an analogous mechanism for alcohol oxidation cata-
lyzed by Rh2(Msip)4/T-HYDRO (Scheme 3). Our results on the selec-
tivity of oxidation in these activated alcohols further support the
idea that the reaction proceeds via a radical intermediate: benzylic,
allylic and propargylic radicals should be more stable than aliphatic
radicals, so alcohol oxidation should occur preferentially at those
positions.
Entry
1
R1
R2
2 (%)b
3 (%)b
1
1a
1b
1c
1d
1e
1f
4-NO2Ph
4-MeOPh
4-BrPh
4-ClPh
Ph
Me
Me
Me
Me
Me
Et
2a (92)
2b (87)
2c (90)
2d (82)
2e (87)
2f (82)
2g (93)
2h (76)d
2i (48)
2j (40)
2k (0)
—
—
2
3
—
4
—
5
—
6
7c
Ph
—
1g
1h
1i
Ph
Ph
—
8
1-Indanol
—
9
3-Pyridenyl
2-Pyridenyl
PhCH2
Me
Me
Me
H
—
10
11
12
13
14
15
16
17
1j
—
1k
1l
—
4-NO2Ph
4-MeOPh
4-BrPh
2l (50)
2m (43)
2n (55)
2o (48)
2p (35)
2q (0)
3l (26)
3m (42)
3n (34)
3o (37)
3p (46)
3q (<5)
1m
1n
1o
1p
1q
H
H
4-ClPh
H
Ph
H
PhCH2
H
aUsing substrate (0.6 mmol, 1.0 equiv.), T-HYDRO (70 wt%) and DCM–
H2O (1:9, v:v).
bIsolated yield after column chromatography.
cReaction was completed in 18 h.
d3-(tert-Butylperoxy)-1-indanone was obtained in 10% isolated yield.
substrate. When the substrate is the primary aliphatic alcohol
2-phenylethanol, only a trace amount of 2-phenylacetic acid (3q)
is observed (Table 2, entry 17).
We also applied the Rh2(Msip)4-catalyzed oxidation system to
allylic and propargylic alcohols (Table 3). Both types of secondary
alcohol are oxidized to the corresponding enone and acetylenic
ketones in moderate to good isolated yield (Table 3, entries 1–6),
although the oxidation is less efficient for allylic alcohols. Trans-
4-phenylbut-3-en-2-ol (1r) and trans-1-cyclohexyl-3-phenylprop-
2-en-1-ol (1t) are oxidized to the corresponding enones 2r and
Table 3. Rh2(Msip)4-catalyzed allylic and propargylic alcohol oxidationa
Table 4. Chemoselective oxidation of several diolsa
Entry
1
X
R
2
Yield (%)b
1
2
3
4
5
6
1r
CH¼CH
CH¼CH
CH¼CH
C≡C
Me
2r
62
50c
69
85
85
83
Entry
4
n
R
5
Yield (%)b
1s
1t
Ph
2s
2t
C6H11
Et
1
2
3
4a
4b
4c
0
3
0
H
5a
5b
5c
23c
43d
85
1u
1v
1w
2u
2v
2w
H
C≡C
Ph
Me
C≡C
C6H11
aUsing substrate (0.6 mmol, 1.0 equiv.), T-HYDRO (70 wt%) and DCM–H2O
aUsing substrate (0.6 mmol, 1.0 equiv.), T-HYDRO (70 wt%) and
(1:9, v:v).
DCM–H2O (1:9, v:v).
bIsolated yield after column chromatography.
bIsolated yield after column chromatography.
c3-Phenyl-2-benzoyloxirane was obtained in 21% isolated yield.
cA small amount of 2-oxo-2-phenylacetic acid was observed (<5%).
dA small amount of 5-oxo-5-phenylpentanoic acid was observed (<5%).
wileyonlinelibrary.com/journal/aoc
Copyright © 2015 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2015, 29, 254–258

Dirhodium(II)-catalyzed selective oxidation of activated alcohols
Experimental
Reagents and Measurements
DCM was distilled from CaH2. Other solvents and commercial re-
agents were used without additional purification, and T-
HYDRO was purchased from Alfa as a 70 wt% aqueous solu-
tion. Substrates 1a–1q, 4a and 4c are commercially available,
while 1r–1t,[27] 1u–1w,[28] 4b[29] and 4d[30] were prepared ac-
cording to reported methods. The dirhodium(II) catalysts Rh2
(Msip)4, Rh2(Tsip)4 and Rh2(PMPsip)4 were prepared as
described.[20] Reaction products were purified using flash col-
umn chromatography with 200–300 mesh silica gel. Products
were visualized using analytical thin-layer chromatography with
UV light (254 nm). 1H NMR spectra were obtained with a Varian
400 MHz spectrometer.
Scheme 1. Oxidation of 1-phenylpentane-1,3-diol.
General Procedure for Alcohol Oxidation
Substrate (0.6 mmol, 1.0 equiv.), Rh2(Msip)4 (0.6 μmol, 0.1 mol%,
5.0 mM solution in DCM, 120 μl) and NaHCO3 (25.2 mg, 0.3 mmol,
50 mol%) were stirred together in 2.0 ml of DCM–H2O (1:9, v:v) at
room temperature in a screw-cap vial. Then 3.0 equiv. of T-HYDRO
(70 wt% in H2O, 1.8 mmol, 0.25 ml) was added in a single delivery
via syringe, and the color of the solution (DCM phase) immediately
turned from light blue to pink red. The vial was tightly capped and
the reaction mixture was stirred at 40°C for 24 h. Then the reaction
mixture was extracted with DCM (3 × 5 ml). The organic extracts
were combined, dried over anhydrous Na2SO4, filtered and con-
centrated under reduced pressure to give crude product, which
was purified via silica gel column chromatography (petroleum
ether–ethyl acetate) to afford the desired product. All isolated
products were characterized using 1H NMR analysis. Spectral
data of all isolated compounds were consistent with the litera-
ture (see supporting information).
Scheme 2. Oxidation of androst-4-ene-3,17-diol.
Table 5. Chemoselective oxidation of several mixed alcoholsa
Entry Substrates
X
R1
R2
Product(s) Selectivity (%)b
1
2
3
1k + 1a
1k + 1s
1k + 1u
—
NO2 CH3 2k + 2a
0 vs 86
0 vs 75
0 vs 80
Acknowledgments
CH¼CH
C≡C
H
H
Ph
Et
2k + 2s
2k + 2u
This work was supported by the National Natural Science Founda-
tion of China (21362038, 21372255 and 21172251), the Research
Fund for the Doctoral Program of Xinjiang Normal University
(XJNUBS1302), and Inorganic Chemistry Key Subject Construction
Project of Xinjiang Normal University (13XSXZ0703).
aUsing substrates (0.3 mmol, 1.0 equiv.), T-HYDRO (70 wt%) and DCM–
H2O (1:9, v:v).
bSelectivity was determined based on 1H NMR analysis.
References
[1] a) M. Hudlicky, Oxidations in Organic Chemistry. ACS Monograph Series,
American Chemical Society, Washington, DC, 1990; b) R. A. Sheldon,
J. K. Kochi, Metal-Catalyzed Oxidations of Organic Compounds,
Academic Press, New York, 1981; c) J.-E. Bäckvall, Modern Oxidation
Methods, 2nd edn, Wiley, Weinheim, 2010.
[2] a) A. J. Mancuso, D. Swern, Synthesis 1981, 165; b) T. T. Tidwell, Synthesis
1990, 857.
[3] a) D. B. Dess, J. C. Martin, J. Org. Chem. 1983, 48, 4155; b) D. B. Dess,
J. C. Martin, J. Am. Chem. Soc. 1991, 113, 7277.
Scheme 3. Proposed mechanism for Rh2(Msip)4-catalyzed alcohol
oxidation.
[4] a)W. J. Klein, in Organic Syntheses by Oxidation with Metal Compounds
(Eds: W. J. Mijs, C. R. H. I. Jonge), Plenum Press, New York, 1986; b)
G. Piancatelli, A. Scettri, M. D’Auria, Synthesis 1982, 245.
[5] a) C. W. Jones, Applications of Hydrogen Peroxide and Derivatives, Royal
Society of Chemistry, Cambridge, 1999; b) G. Strukul, Catalytic
Oxidations with Hydrogen Peroxide as Oxidant, Kluwer, Dordrecht,
1992; c) T. Mallat, A. Baiker, Chem. Rev. 2004, 104, 3037.
[6] K. B. Sharpless, T. R. Verhoeven, Aldrichim. Acta 1979, 12, 63.
[7] For vanadium-catalyzed oxidation of alcohols with TBHP, see:a)L. Rout,
P. Nath, T. Punniyamurthy, Adv. Synth. Catal. 2007, 349, 846; b)
W. Trakarnpruk, P. Hoonsart, Chin. J. Catal. 2007, 28, 290.
Conclusions
We have developed a novel, mild and efficient protocol for oxidiz-
ing benzylic, allylic and propargylic alcohols using Rh2(Msip)4 as cat-
alyst and T-HYDRO in aqueous solvent. This catalytic system allows
chemoselective oxidation of secondary activated alcohols, while
leaving other intramolecular alkyl hydroxyls untouched.
Appl. Organometal. Chem. 2015, 29, 254–258
Copyright © 2015 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

A. Wusiman and C.-D. Lu
[8] For chromium-catalyzed oxidation of alcohols with TBHP, see: a)
J. Muzart, Tetrahedron Lett. 1987, 28, 2133; b) B. M. Choudary,
A. Durgaprasad, V. L. K. Valli, Tetrahedron Lett. 1990, 31, 5785; c)
J. Muzart, Chem. Rev. 1992, 92, 113; d) N. B. Barhate, M. Sasidharan,
A. Sudalai, R. D. Wakharkar, Tetrahedron Lett. 1996, 37, 2067; e)
Z. Lounis, A. Riahi, F. Djafri, J. Muzart, Appl. Catal. A 2006, 309, 270.
[9] For manganese-catalyzed oxidation of alcohols with TBHP, see:a)
S. Bose, A. Pariyar, A. N. Biswas, P. Das, P. Bandyopadhyay, Catal.
Commun. 2011, 12, 446; b) K. Ibrahim, K. Mehmet, Turk. J. Chem.
2012, 36, 827; c) V. Mahdavi, M. Mardani, J. Chem. Sci. 2012, 124, 1107.
[10] For iron-catalyzed oxidation of alcohols with TBHP, see: D. H. R. Barton,
S. D. Bévière, B. M. Chabot, W. Chavasiri, D. K. Taylor, Tetrahedron Lett.
1994, 35, 4681.
[11] For cobalt-catalyzed oxidation of alcohols with TBHP, see: a) S. Iyer,
J. P. Varghese, Synth. Commun. 1995, 25, 2261; b) R. Chakrabarty,
P. Sarmh, B. Saha, S. Chakravorty, B. K. Das, Inorg. Chem. 2009, 48,
6371; c) M. Özer, F. Yılmaz, H. Erer, I. Kani, Ö. Bekaroğlu, Appl.
Organometal. Chem. 2009, 23, 55; d) M. H. Peyrovi, V. Mahdavi,
M. A. Salehi, R. Mahmoodian, Catal. Commun. 2005, 6, 476; e)
P. Sarmah, R. Chakrabarty, P. Phukan, B. K. Das, J. Mol. Catal. A 2007,
268, 36.
[12] For copper-catalyzed oxidation of alcohols with TBHP, see: a)
L. Feldberg, Y. L. Sasson, J. Chem. Soc. Chem. Commun. 1994, 1807; b)
G. Rothenberg, L. Feldberg, H. Wiener, Y. Sasson, J. Chem. Soc. Perkin
Trans. 2 1998, 2429; c) G. Ferguson, A. N. Ajjou, Tetrahedron Lett.
2003, 44, 9139; d) J. Boudreau, M. Doucette, A. N. Ajjou, Tetrahedron
Lett. 2006, 47, 1695; e) C. Liu, J. Y. Han, J. Wang, Synlett. 2007, 4, 643;
f) M. Rong, C. Liu, J. Han, W. Sheng, Y. Zhang, H. Wang, Catal. Lett.
2008, 125, 52; g) S. Mannam, G. Sekar, Tetrahedron Lett. 2008, 49,
2457; h) M.-X. Zhu, B.-D. Li, P. He, X. Wei, Y.-Z. Yuan, Tetrahedron
2008, 64, 9239; i) P. Sarmah, R. K. Barman, P. Purkayastha, S. J. Bora,
P. Phukan, B. K. Das, Indian J. Chem. A 2009, 48, 637; j) P. Sarmah,
B. K. Das, P. Phukan, Catal. Commun. 2010, 11, 932; k) R. Das,
D. Chakraborty, Appl. Organometal. Chem. 2011, 25, 437; l) C. Y. Han,
M. Yu, W. J. Sun, X. Q. Yao, Synlett. 2011, 16, 2363; m) K. C. Weerasiri,
A. E. V. Gorden, Eur. J. Org. Chem. 2013, 1546; n) K. C. Weerasiri,
A. E. V. Gorden, Tetrahedron 2014, 70, 7962.
333; b) M. Tanaka, T. Kobayashi, T. Sakakura, Angew. Chem. Int. Ed. Engl.
1984, 23, 518; c) S.-I. Murahashi, T. Naota, N. Nakajima, Tetrahedron Lett.
1985, 26, 925; d) S. I. Murahashi, T. Naota, Synthesis 1993, 433; e)
W. H. Fung, W. Y. Yu, C. M. Che, J. Org. Chem. 1998, 63, 2873; f)
W.-H. Cheung, W.-Y. Yu, W.-P. Yip, N.-Y. Zhu, C.-M. Che, J. Org. Chem.
2002, 67, 7716; g) P. Singh, A. K. Singh, Organometallics 2010, 29,
6433; h) J. Tauchman, B. Therrien, G. Süss-Fink, P. Petrštěpnička,
Organometallics 2012, 31, 3985.
[16] For rhodium-catalyzed oxidation of alcohols with TBHP, see: a) P. Muller,
H. Idmoumaz, J. Organometal. Chem. 1988, 345, 187; b) C. J. Moody,
F. N. Palmer, Tetrahedron Lett. 2002, 43, 139.
[17] For gold-catalyzed oxidation of alcohols with TBHP, see: H. Li, B. Guan,
W. Wang, D. Xing, Z. Fang, X. Wan, L. Yang, Z. Shi, Tetrahedron 2007, 63,
8430.
[18] For other metal-catalyzed oxidations of alcohols with TBHP, see: a)
S. J. Singh, R. V. Jayaram, Synth. Commun. 2012, 42, 299;
b) M. L. Patil, S. R. Maujan, H. B. Borate, B. S. Uphade, Arkivoc 2007, 70.
[19] D. Bogdal, M. Lukasiewicz, Synlett 2000, 143.
[20] A. Wusiman, X. Tusun, L. Chong-Dao, Eur. J. Org. Chem. 2012, 3088.
[21] H. Choi, M. P. Doyle, Org. Lett. 2007, 9, 5349.
[22] K. P. Peterson, R. C. Larock, J. Org. Chem. 1998, 63, 3185.
[23] Similar observations were reported for chromium-catalyzed benzylic
oxidation, see: J. Muzart, A. N’Ait Ajjou, J. Mol. Catal. 1994, 92, 141.
[24] a) Y. B. Koh, G. G. Christoph, Inorg. Chem. 1978, 17, 2590; b)
S. A. Johnson, H. R. Hunt, H. M. Neuman, Inorg. Chem. 1963, 2, 960.
[25] a) A. J. Catino, R. E. Forslund, M. P. Doyle, J. Am. Chem. Soc. 2004, 126,
13622; b) E. C. McLaughlin, H. Choi, K. Wang, G. Chiou, M. P. Doyle,
J. Org. Chem. 2009, 74, 730; c) E. C. McLaughlin, M. P. Doyle, J. Org.
Chem. 2008, 73, 4317.
[26] a) D. H. R. Barton, V. N. Le Gloahec, H. Patin, F. Launay, New J. Chem.
1998, 559; b) D. H. R. Barton, V. N. Le Gloahec, Tetrahedron 1998, 54,
15457.
[27] I. D. G. Watson, S. A. Styler, A. K. Yudin, J. Am. Chem. Soc. 2004, 126,
5086.
[28] K. Tanaka, T. Shoji, Org. Lett. 2005, 17, 3561.
[29] Y. Brunel, G. Rousseau, J. Org. Chem. 1996, 61, 5793.
[30] F. Berti, S. Bincoletto, I. Donati, G. Fontanive, M. Fregonese, F. Benedetti,
Org. Biomol. Chem. 2011, 9, 1987.
[13] For zirconium-catalyzed oxidation of alcohols with TBHP, see: a)
K. Kaneda, Y. Kawanishi, S. Teranishi, Chem. Lett. 1984, 1481; b)
K. Krohn, K. Khanbabac, H. Rieger, Chem. Ber. 1990, 123, 1357; c)
K. Krohn, I. Vinke, H. Adam, J. Org. Chem. 1996, 61, 1467.
[14] For molybdenum-catalyzed oxidation of alcohols with TBHP, see:
Y. Masuyama, M. Takahashi, Y. Kurusu, Tetrahedron Lett. 1984, 25, 4417.
[15] For ruthenium-catalyzed oxidation of alcohols with TBHP, see: a) Y. Tuji,
T. Ohta, T. Ido, H. Minbu, Y. Watanabe, J. Organometal. Chem. 1984, 270,
Supporting Information
Additional supporting information may be found in the online ver-
sion of this article at the publisher’s web-site.
wileyonlinelibrary.com/journal/aoc
Copyright © 2015 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2015, 29, 254–258