Mn(III)-based C-C bond formation: Regioselective α′-allylation of various α,β-unsaturated, α and β-alkoxy α,β-unsaturated ketones

Article abstract of DOI:10.1016/j.tet.2005.06.031

The Manganese(III)-based regioselective α′-keto radical generation of unsaturated ketones is a versatile synthetic procedure with broad applicability. The generated α′-keto radical slowly creates a metal enolate in a solvent at reflux. The resultant metal

Full text of DOI:10.1016/j.tet.2005.06.031

Tetrahedron 61 (2005) 8212–8217
Mn(III)-based C–C bond formation: regioselective a0-allylation of
various a,b-unsaturated, a and b-alkoxy a,b-unsaturated ketones
b
Cihangir Tanyelia, and Devrim Ozdemirhan
¨
*
aDepartment of Chemistry, Middle East Technical University, 06531 Ankara, Turkey
b
˙
Department of Chemistry, Abant Izzet Baysal University, 14280 Bolu, Turkey
Received 8 April 2005; revised 26 May 2005; accepted 9 June 2005
Available online 11 July 2005
Abstract—The Manganese(III)-based regioselective a0-keto radical generation of unsaturated ketones is a versatile synthetic procedure with
broad applicability. The generated a0-keto radical slowly creates a metal enolate in a solvent at reflux. The resultant metal enolate affords
the corresponding a0-allylated a,b-unsaturated ketones in good yields. This method is the first example of the metal mediated regioselective
a0-allylation of a,b-unsaturated ketones. The ketones that have a or b-alkoxy groups also work efficiently.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
a new method in the field of regioselective direct allylation
of a,b-unsaturated ketones. Recently, we reported a
complete regioselectivity related to the metal-mediated
a0-allylation of enones.8f The allylation of enones mediated
by Mn(III) shows exclusive selectivity toward the a0-position
of a,b-unsaturated ketones. We describe here, the results of
the Mn(OAc)3 based allylation of various a,b-unsatur-
ated ketones and a- or b-alkoxy a,b-unsaturated ketones.
The empirical endeavour on the synthesis of targets with
wide complexity has resulted in the development of reac-
tions that emphasize chemo-, regio-, and stereoselectivity.
In defining the strategies and reactions to construct complex
molecules, regioselectivity is required.1 Metal-mediated
allylation generally has a central position in the synthesis of
various complex natural products. A wide variety of allyl-
ations are well known in the literature as useful methods for
carbon–carbon bond formation, that is, metal-mediated allyl
addition to carbonyl,2,3 and the direct allylation on the
a-position of ketones.4,5 A considerable challenge is to
affect a high regioselectivity between carbonyl carbons and
the a and a0-positions of a,b-unsaturated ketones.
2. Results and discussion
As a starting point, we have studied the use of
manganese(III) acetate as a potentially useful mediator for
the metal-promoted regioselective a0-allylation reaction of
various enones. When 3-methyl-cyclopent-2-enone 1c
(entry 3) was stirred with 2 equiv of Mn(OAc)3$2H2O and
1 equiv of allyl bromide in benzene for 8 h at reflux, 81% of
5-allyl-3-methyl-cyclopent-2-enone 2c was isolated. When
3 equiv of Mn(OAc)3$2H2O was used, the isolated yield
of the allylation product substantially decreased to 53 and
25% of the a0-acetoxylation product9 that was isolated.
Changing the amount of Mn(OAc)3$2H2O to 1 equiv
decreased the yield of the allylation product too (64%), and
no a0-acetoxylation product was observed. The stoichiometric
amount of manganese(III) acetate appears to be critical.
In the last decade, Mn(III)-based oxidative free-radical
reactions have been developed into a versatile protocol for
the formation of highly functionalized products from simple
precursors.6 In 1976, Williams and Hunter reported that
the Mn(OAc)3$2H2O oxidation of enones in HOAc at
reflux affords a0-acetoxy enones in low yields.7 In
connection with our synthetic studies with manganese(III)
acetate,8 we found that trapping of the a0-keto radicals that
were obtained from b-alkoxy a,b-unsaturated ketones with
benzene as solvent is much faster than acetoxylation,
affording good yields of tandem oxidation products.8d These
noteworthy results prompted us toward the development of
As a natural extension of this study, we have pursued a
complementary investigation aimed at subjecting various a,
b-unsaturated cyclic ketones to comparable scrutiny. Subse-
quently, a variety of cyclopentenones and cyclohexenones
were tested with this allylation method (Scheme 1).
Keywords: Enones; Manganese and compounds; Allylation.
*
Corresponding author. Tel.: C90 312 210 32 22; fax: C90 312 210 12
80; e-mail: tanyeli@metu.edu.tr
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.06.031

¨
C. Tanyeli, D. Ozdemirhan / Tetrahedron 61 (2005) 8212–8217
8213
cyclohexenone was chosen as a model compound. The
reaction of 3e in benzene with 2 equiv of Mn (OAc)3$2H2O
and 1 equiv of allyl bromide for 8 h at reflux affords 75%
of 6-allyl-3-ethoxy-5,5-dimethyl-2-cyclohexenone 4e
(entry 5). Selected examples are shown in Table 2 (Scheme 2).
In order to test the allylation reaction, whether it proceeds
by a radical mechanism or by a nucleophilic substitution,
3-ethoxy-5,5-dimethyl-2-cyclohexenone 3e and 3-methyl-
2-cyclohexenone 2e were reacted with crotyl bromide under
the same conditions. Both afforded the nucleophilic
substitution products 5a and 5b in 49 and 52% yields,
respectively, (Scheme 3); the regioselectivity of the
allylation implies that the reaction proceeds via an SN2
mechanism and is not radical in nature.12
Scheme 1.
Selected examples are shown in Table 1. It was found that
various cyclopentenones and cyclohexenones were effi-
ciently allylated. In general, cyclopentenone derivatives
afford higher chemical yields than cyclohexenone deriva-
tives. We could not observe any substantial change in the
chemical yields related to the substituents on the substrates.
In entry 1, 2 and 3, the dimerized allylated products were
isolated.10 These results can strongly support the formation
of a radical on the a0-position of enone systems. We
attempted to replace benzene with a more innocuous solvent
toluene in entries 1–3 and obtained a 5–7% decrease in the
yields.11 Regioselective allylation was also tested with an
acyclic substrate mesityl oxide (entry 9) and the allylated
acylic product 2i was obtained in an acceptable yield.
From these results in particular, with the results of the
allylation where it was tested with different allyl side chains,
we subsequently proposed a reaction mechanism as is
shown in Scheme 4. The reaction presumably proceeds via
the formation of Mn(III) enolate 6, which by way of one
electron oxidation, gives the a0-keto radical 7.13 The second
equiv of Mn(OAc)3 slowly forms the Mn(II) enolate 8.
Alkylation of this metal enolate with allyl bromide yields
the a0-allyl a,b-unsaturated cyclic ketone 2. Vinogradov
et al. reported that a0-keto radicals generated by higher
ketones would result in secondary radicals, which dimerize
or lead to tertiary radicals, which are prone to further
oxidation.14 In accordance with this conclusion, in this
current study the dimerization of product 2 was observed for
entries 1, 2 and 3 as was mentioned above.
We also examined the allylation reaction of b-alkoxy and
a-alkoxy a,b-unsaturated ketones that play an important
role in the synthesis of quassinoids and prostaglandines,
respectively.
In the first part of that study, 3-ethoxy-5,5-dimethyl-2-
Table 1. a0-Allylation of a,b-unsaturated enones mediated by Mn(OAc)3 in benzene
Entry
Reactant 1
Product
211
2a
Yield (%)
79
Time (h)
8
1
2
3
2b
2c
80
81
8
8
4
5
6
2d
2e
2f
83
78
68
10
12
12
7
2g
67
10
8
9
2h
2i
72
52
12
14

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C. Tanyeli, D. Ozdemirhan / Tetrahedron 61 (2005) 8212–8217
8214
Table 2. a0-Allylation of a-alkoxy and b-alkoxy a,b-unsaturated enones mediated with Mn(OAc)3
Entry
1
Reactant 3
Product
4
Yield (%)
69
Time (h)
7
4a
2
3
4b
4c
72
67
6
7
4
5
4d
4e
65
75
5
8
6
7
8
4f
75
72
65
9
4g
4h
12
11
In conclusion, manganese(III) acetate is highly effective for
mediating the a0-allylations of a,b-unsaturated cyclic
ketones, a-alkoxy and b-alkoxy a,b-unsaturated cyclic
ketones. This one-step reaction offers a complete regio-
selectivity towards the a0-allylation of cyclic enones and
opens up a new class of Mn(OAc)3 reactions.
Scheme 2.
3. Experimental
Nuclear magnetic resonance spectra were acquired on a
Bruker Spectrospin Avance DPX 400 spectrometer at
400 MHz for 1H and 100 MHz for 13C, in CDCl3. Chemical
shifts are given in ppm from tetramethylsilane. IR spectra
were obtained using a Perkin-Elmer Model 1600 series
FT-IR spectrometer and are reported in cmK1. Mass spectra
were recorded with a Varian MAT 212. Flash chromato-
graphy: Merck silica gel 60 (230–400 mesh).
Scheme 3.
Scheme 4.

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C. Tanyeli, D. Ozdemirhan / Tetrahedron 61 (2005) 8212–8217
8215
3.1. General procedure for the Mn(OAc)3 based
allylation of a,b-unsaturated ketones 1 and a and
b-alkoxy a,b-unsaturated ketones 3
44.5, 38.1, 36.0, 17.4, 9.8; HRMS (EI): MC, found
150.1040. C10H14O requires 150.1045.
3.1.5. 6-Allyl-3-methyl-cyclohex-2-enone 2e. (0.82 g,
78%) as a colourless oil; nmax (neat) 3024, 2923, 2855,
2357, 1659 cmK1; dH (400 MHz, CDCl3) 5.78 (1H, s,
]CHCO), 5.65–5.76 (1H, m, CH2CH]CH2), 5.09 (1H,
d, JZ18.2 Hz, CHaHb]CH), 4.96 (1H, d, JZ9.2 Hz,
CHaHb]CH), 2.53–2.56 (1H, m, CHCO), 2.15–2.23 (3H,
m, CH2CH]CH2), 1.98–2.09 (2H, m, CHaHbCHCO), 1.87
(3H, s, Me), 1.58–1.70 (1H, m, CHaHbCHCO); dC
(100.6 MHz, CDCl3) 201.2, 162.3, 136.7, 126.7, 117.0,
45.4, 34.1, 30.7, 27.6, 24.6; HRMS (EI): MC, found
150.1044. C10H14O requires 150.1045.
A mixture of Mn(OAc)3$2H2O (3.25 g, 14.0 mmol) in
benzene (150 ml) was heated at reflux for 45 min using a
Dean-Stark trap. The mixture was then cooled to room
temperature and the a,b-unsaturated ketone (7.0 mmol) and
allyl bromide (0.85 g, 7.0 mmol) were added. The mixture
was heated to reflux until its dark brown colour disappeared.
In addition, it was monitored by TLC. The reaction mixture
was diluted with an equal amount of ethyl acetate, and the
organic phase was washed with 1 M HCl followed by
saturated NaHCO3 and brine. The organic phase was dried
over MgSO4 and evaporated in vacuo. The crude product
was separated by way of flash column chromatography
using ethyl acetate/hexane as an eluent to afford the product.
3.1.6. 6-Allyl-3,5,5-trimethyl-cyclohex-2-enone 2f.
(0.85 g, 68%) as a colourless oil; nmax (neat) 2956, 1665,
1445, 1370 cmK1; dH (400 MHz, CDCl3) 5.79–5.93 (2H,
m, ]CHCO and CH]CH2), 5.04 (1H, d, JZ15.2 Hz,
CHaHb]CH), 4.96 (1H, d, JZ11.3 Hz, CHaHb]CH),
2.15–2.31 (4H, m, CH2CH and CH2CMe2), 2.08–2.12
(1H, m, CHCO), 1.91 (3H, s, MeC]), 1.05 (3H, s,
Me2C), 0.96 (3H, s, Me2C); dC (100.6 MHz, CDCl3)
202.1, 158.5, 138.0, 125.3, 115.7, 57.5, 45.1, 36.7, 30.7,
29.1, 24.6, 24.5; HRMS (EI): MC, found 178.1355.
C12H18O requires 178.1358.
3.1.1. 5-Allyl-cyclopent-2-enone 2a. (0.68 g, 79%) as a
colourless oil; nmax (neat) 2960, 2860, 1707, 1590 cmK1; dH
(400 MHz, CDCl3) 7.68–7.70 (1H, m, HC]CHCO), 6.19
(1H, dd, JZ2.1, 7.6 Hz, HC]CHCO), 5.70–5.81 (1H, m,
CH2]CHCH2), 5.08 (1H, d, JZ19.3 Hz, CHaHb]CH),
5.04 (1H, d, JZ11.1 Hz, CHaHb]CH), 2.80–2.86 (1H, m,
CH2CHCO), 2.52–2.57 (1H, m, CHaHb), 2.39–2.44 (2H, m,
CH2), 2.08–2.18 (1H, m, CHaHb); dC (100.6 MHz, CDCl3)
212.0, 164.1, 135.6, 134.2, 117.2, 44.4, 35.6, 35.2; HRMS
(EI): MC, found 122.0737. C8H10O requires 122.0732.
3.1.7. 6-Allyl-4,4-dimethyl-cyclohex-2-enone 2g. (0.77 g,
67%) as a colourless oil; nmax (neat) 3211, 2892, 1715, 1665,
1515, 1289 cmK1; dH (400 MHz, CDCl3) 6.40 (1H, d, JZ
10.0 Hz, CH]CHCO), 5.63 (1H, d, JZ10.0 Hz,
CH]CHCO), 5.59–5.62 (1H, m, CH]CH2), 4.87 (1H, d,
JZ17.1 Hz, CHaHb]CH), 4.84 (1H, d, JZ9.1 Hz, CHa-
Hb]CH), 2.47–2.53 (1H, m, CHCO), 2.26–2.34 (1H, m,
CHaHbCH]), 1.85–1.92 (1H, m, CHaHbCH]), 1.66 (1H,
dd, JZ4.6, 13.4 Hz, CHaHbCHCO), 1.41 (1H, t, JZ
13.4 Hz, CHaHbCHCO), 0.98 (3H, s, Me2C), 0.95 (3H, s,
Me2C); dC (100.6 MHz, CDCl3) 200.9, 159.2, 136.6, 127.0,
117.0, 57.3, 42.5, 42.0, 34.0, 30.9, 25.8; HRMS (EI): MC,
found 164.1207. C11H16O requires 164.1202.
3.1.2. 5-Allyl-2-methyl-cyclopent-2-enone 2b. (0.76 g,
80%) as a colourless oil; nmax (neat) 2910, 1682, 1615,
1431 cmK1; dH (400 MHz, CDCl3) 7.28 (1H, d, JZ2.1 Hz,
HC]CMeCO), 5.70–5.80 (1H, m, CH2CH]CH2), 5.07
(1H, d, JZ17.1 Hz, CHaHb]CH), 5.02 (1H, d, JZ10.7 Hz,
CHaHb]CH), 2.65–2.71 (1H, m, CHCO), 2.53–2.58 (1H,
m, CHa Hb), 2.42–2.45 (1H, m, CHaHb), 2.23–2.29 (1H, m,
CHaHb), 2.10–2.15 (1H, m, CHaHb), 1.78 (3H, s, MeCCO);
dC (100.6 MHz, CDCl3) 211.7, 157.4, 141.6, 135.9, 117.0,
44.6, 35.9, 33.0, 10.6; HRMS (EI): MC, found 136.0890.
C9H12O requires 136.0888.
3.1.3. 5-Allyl-3-methyl-cyclopent-2-enone 2c. (0.77 g,
81%) as a colourless oil; nmax (neat) 3066, 2973, 1690,
1648 cmK1; dH (400 MHz, CDCl3) 5.92 (1H, s, ]CHCO),
5.70–5.79 (1H, m, CH2CH]CH2), 5.07 (1H, d, JZ17.3 Hz,
CHaHb]CH), 5.03 (1H, d, JZ10.5 Hz, CHaHb]CH), 2.69
(1H, dd, JZ6.3, 18.1 Hz, CHCO), 2.49–2.63 (2H, m,
CH2C]), 2.29 (1H, d, JZ18.1 Hz, CHaHbCHCO), 2.13–
2.14 (1H, m, CHaHbCHCO), 2.12 (3H, s); dC (100.6 MHz,
CDCl3) 211.4, 178.0, 135.7, 130.2, 117.0, 46.1, 39.2, 35.9,
19.7; HRMS (EI): MC, found 136.0893. C9H12O requires
136.0888.
3.1.8. 6-Allyl-4,4-diphenyl-cyclohex-2-enone 2h. (1.45 g,
72%) as a colourless oil; nmax (neat) 3024, 2931, 2885, 1665,
1589, 1437 cmK1; dH (400 MHz, CDCl3) 7.20–7.47 (10H,
m, Ph2C), 7.15 (1H, d, JZ10.1 Hz, CH]CHCO); 6.21
(1H, d, JZ10.1 Hz, CH]CHCO), 5.67–5.77 (1H, m,
CH]CH2), 5.02–5.05 (2H, m, CH]CH2), 2.67–2.75 (2H,
m, CH2CH]), 2.32–2.42 (2H, m, CH2CHCO), 2.04–2.17
(1H, m, CHCO); dC (100.6 MHz, CDCl3) 199.8, 155.2,
148.0, 143.1, 135.6, 129.1, 128.8, 128.7, 128.6, 128.5,
128.0, 127.9, 127.8, 127.2, 127.0, 126.7, 117.1, 49.9, 42.7,
41.2, 33.2; HRMS (EI): MC, found 288.1519. C21H20O
requires 288.1514.
3.1.4. 5-Allyl-2,3-dimethyl-cyclopent-2-enone 2d. (0.87 g,
83%) as a colourless oil; nmax (neat) 3066, 2973, 2914, 1690,
1648 cmK1; dH (400 MHz, CDCl3) 5.69–5.80 (1H, m,
CH2CH]CH2), 5.06 (1H, d, JZ17.1 Hz, CHaHb]CH),
5.01 (1H, d, JZ9.5 Hz, CHaHb]CH), 2.64 (1H, dd, JZ5.8,
19.3 Hz, CHCO), 2.52–2.62 (1H, m, CHaHbCH]CH2),
2.42–2.44 (1H, m, CHaHbCH]CH2), 2.05–2.10 (1H, m,
CHaHbCHCO), 2.21 (1H, d, JZ19.3 Hz, CHaHbCHCO),
2.04 (3H, s, MeCCO), 1.69 (3H, s, MeC]CMeCO); dC
(100.6 MHz, CDCl3) 211.1, 169.1, 136.0, 135.8, 116.8,
3.1.9. 2-Methyl octa-2,7-dien-4-one 2i. (0.5 g, 52%) as a
;
colourless oil; nmax (neat) 3079, 1595, 1692, 981, 882 cmK1
dH (400 MHz,CDCl3)6.00(1H, s,Me2C]CHCO),5.71–5.82
(1H, m, CH2]CH), 4.96 (1H, d, JZ15.2 Hz, CHaHb]CH),
4.90 (1H, d, JZ8.9 Hz, CHaHb]CH), 2.43 (2H, t, JZ
7.0 Hz, COCH2CH2), 2.25–2.30 (2H, m, COCH2CH2), 2.08
(3H, s, Me2C]), 1.82 (3H, s, Me2C]); dC (100.6 MHz,
CDCl3) 200.5, 155.6, 137.9, 124.1, 115.3, 43.6, 28.5, 28.0,

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C. Tanyeli, D. Ozdemirhan / Tetrahedron 61 (2005) 8212–8217
8216
21.1; HRMS (EI): MHC, found 139.1116. C9H14O requires
139.1123.
]CHCO), 4.94 (1H, d, JZ17.2 Hz, CHaHb]CH), 4.90
(1H, d, JZ10.3 Hz, CHaHb]CH), 3.82 (2H, q, JZ7.1 Hz,
MeCH2O), 2.55 (1H, d, JZ17.6 Hz, CHCO), 2.24–2.31
(2H, m, CHaHbCH]CH2 and CHaHbCMe2), 2.15 (1H, d, JZ
17.6 Hz, CHaHbCH]CH2), 1.99–2.03 (1H, m, CHaHbCMe2),
1.29 (3H, t, JZ7.1 Hz, MeCH2), 1.02 (3H, s, MeCH2), 0.93
(3H, s, MeCH2); dC (100.6 MHz, CDCl3) 201.6, 174.6,
138.1, 115.5, 101.1, 64.4, 61.8, 57.3, 42.4, 35.5, 31.2, 14.5,
14.4; HRMS (EI): MC, found 208.1463. C13H20O2 requires
208.1464.
3.1.10. 5-Allyl-3-ethoxy-cyclopent-2-enone 4a. (0.72 g,
69%) as a colourless oil; nmax (neat) 2950, 1125, 1700,
1560 cmK1; dH (400 MHz, CDCl3) 5.65–5.74 (2H, m,
]CHCO and CH]CH2), 5.02 (1H, d, JZ18.9 Hz, CHa-
Hb]CH), 4.98 (1H, d, JZ11.0 Hz, CHaHb]CH), 3.97
(2H, q, JZ7.1 Hz, MeCH2O), 2.63 (1H, dd, JZ6.8,
17.6 Hz, CHCO), 2.47–2.53 (2H, m, CH2), 2.27 (1H, dd,
JZ1.7, 17.6 Hz, CHaHbCH]CH2), 2.00–2.14 (1H, m,
CHaHbCH]CH2), 1.34 (3H, t, JZ7.1 Hz, MeCH2O); dC
(100.6 MHz, CDCl3) 207.8, 189.4, 135.7, 113.2, 104.3,
68.0, 44.7, 35.9, 34.5, 14.5; HRMS (EI): MC, found
166.0991. C10H14O2 requires 166.0994.
3.1.15. 5-Allyl-2-ethoxy-3-methyl-cyclopent-2-enone 4f.
(0.95 g, 75%) as a colourless oil; nmax (neat) 3060, 2970,
1680, 1645, 1115 cmK1; dH (400 MHz, CDCl3) 5.63–5.77
(1H, m, CH]CH2), 5.01 (1H, d, JZ18.6 Hz, CHaHb]CH),
4.99 (1H, d, JZ10.4 Hz, CHaHb]CH), 4.04–4.18 (2H, m,
MeCH2O), 2.49 (1H, dd, JZ6.4, 16.8 Hz, CHCO), 2.48
(1H, dd, JZ6.4, 17.9 Hz, CHaHbCH]CH2), 2.32–2.35
(1H, m, CHaHbCH]CH2), 2.02–2.10 (2H, m, CH2CHCO),
1.90 (3H, s, MeC]), 1.19 (3H, t, JZ7.0 Hz, MeCH2); dC
(100.6 MHz, CDCl3) 205.2, 154.5, 151.6, 135.5, 117.2,
66.4, 43.0, 20.7, 33.9, 16.0, 15.2; HRMS (EI): MC, found
180.1153. C11H16O2 requires 180.1150.
3.1.11. 5-Allyl-3-ethoxy-2-methyl-cyclopent-2-enone 4b.
(0.9 g, 72%) as a colourless oil; nmax (neat) 2900, 1675,
1400, 1120 cmK1; dH (400 MHz, CDCl3) 5.64–5.74 (1H, m,
CH]CH2), 5.02 (1H, d, JZ18.8 Hz, CHaHb]CH), 4.98
(1H, d, JZ10.5 Hz, CHaHb]CH), 4.15–4.32 (2H, m,
MeCH2O), 3.07 (1H, dd, JZ6.6, 18.9 Hz, CHaHbCHCO),
2.99 (1H, dd, JZ6.7, 18.5 Hz, CHCO), 2.79 (1H, d, JZ
18.9 Hz, CHaHbCHCO), 1.47–2.56 (1H, m, CH2]CHCHaHb),
1.98–2.11 (1H, m, CH2]CHCHaHb), 1.71 (3H, s, MeC]),
1.37 (3H, t, JZ7.0 Hz, MeCH2O); dC (100.6 MHz, CDCl3)
201.0, 178.8, 136.0, 119.1, 117.1, 66.2, 45.7, 45.2, 40.1,
15.7, 7.5; HRMS (EI): MC, found 180.1156. C11H16O2
requires 180.1150.
3.1.16. 5-Allyl-2-ethoxy-3-ethyl-cyclopent-2-enone 4g.
(0.9 g, 72%) as a colourless oil; nmax (neat) 3055, 2842,
1674, 1145, 1209 cmK1; dH (400 MHz, CDCl3) 5.58–5.78
(1H, m, CH]CH2), 5.02 (1H, d, JZ17.1 Hz, CHaHb]CH),
4.97 (1H, d, JZ10.7 Hz, CHaHb]CH), 4.03–4.18 (2H, m,
MeCH2O), 2.50 (1H, dd, JZ6.4, 18.1 Hz, CHCO), 2.44–
2.49 (1H, m, CHaHbCH]CH2), 2.34 (2H, q, JZ7.6 Hz,
MeCH2C]), 1.96–2.10 (3H, m, CHaHbCH]CH2 and
CH2CHCO), 1.18 (3H, t, JZ7.0 Hz, MeCH2O), 1.04 (3H,
t, JZ7.6 Hz, MeCH2C]); dC (100.6 MHz, CDCl3) 205.6,
160.0, 135.5, 117.2, 114.7, 66.5, 42.9, 36.0, 31.1, 22.3, 16.0,
11.9; HRMS (EI): MC, found 194.1311. C12H18O2 requires
194.1307.
3.1.12. 6-Allyl-3-ethoxy-cyclohex-2-enone 4c. (0.74 g,
67%) as a colourless oil; nmax (neat) 3020, 2915, 2852,
1650, 1110 cmK1; dH (400 MHz, CDCl3) 5.75–5.86 (1H, m,
CH]CH2), 5.35 (1H, s, ]CHCO), 5.08 (1H, d, JZ
15.2 Hz, CHaHb]CH), 5.05 (1H, d, JZ5.1 Hz, CHa-
Hb]CH), 3.88–3.94 (2H, m, MeCH2O), 2.64–2.68 (1H,
m, CHCO), 2.43 (2H, t, JZ5.3 Hz, CH2CH]CH2), 2.25–
2.28 (1H, m, CHaHbCH2CHCO), 2.05–2.19 (2H, m,
CH2CHO), 1.71–1.75 (1H, m, CHaHbCH2CHCO), 1.38
(3H, t, JZ7.0 Hz, MeCH2); dC (100.6 MHz, CDCl3) 200.5,
182.6, 137.0, 116.8, 101.3, 64.6, 41.8, 34.2, 27.4, 25.3, 14.4;
HRMS (EI): MC, found 180.1142. C11H16O2 requires
180.1150.
3.1.17. 6-Allyl-2-ethoxy-cyclohex-2-enone 4h. (0.82 g,
65%) as a colourless oil; nmax (neat) 3015, 2920, 2850,
1690, 1090 cmK1; dH (400 MHz, CDCl3) 5.75 (1H, t, JZ
4.1 Hz, CH]COEt), 5.66–5.76 (1H, m, CH]CH2), 5.00
(1H, d, JZ14.9 Hz, CHaHb]CH), 4.97 (1H, d, JZ8.3 Hz,
CHaHb]CH), 3.68 (2H, q, JZ7.0 Hz, MeCH2O), 2.54–
2.60 (1H, m, CHCO), 2.33–2.39 (3H, m, CH2CH] and
CHaHbCH]COEt), 2.10–2.14 (1H, m, CHaHbCH]COEt),
1.94–2.01 (1H, m, CHaHbCHCO), 1.61–1.69 (1H, m,
CHaHbCHCO), 1.17 (3H, t, JZ7.0 Hz, MeCH2O); dC
(100.6 MHz, CDCl3) 196.2, 150.8, 136.4, 117.2, 116.7,
47.3, 35.4, 34.2, 27.8, 23.4, 14.8; HRMS (EI): MC, found
180.1154. C11H16O2 requires 180.1150.
3.1.13. 6-Allyl-3-ethoxy-4,4-dimethyl-cyclohex-2-enone
4d. (0.95 g, 65%) as a colourless oil; nmax (neat) 3210,
2890, 1710, 1662, 1115 cmK1; dH (400 MHz, CDCl3) 5.66–
5.76 (1H, m, CH]CH2), 5.16 (1H, s, ]CHCO), 4.99 (1H,
dd, JZ15.1 Hz, CHaHb]CH), 4.96 (1H, d, JZ7.7 Hz,
CHaHb]CH), 3.72–3.89 (2H, m, MeCH2O), 2.64–2.70
(1H, m, CHCO), 2.31–2.39 (1H, m, CHaHbCH]CH2),
1.97–2.12 (1H, m, CHaHbCH]CH2), 1.70 (1H, dd, JZ
4.8, 13.3 Hz, CHaHbCHCO), 1.54 (1H, t, JZ13.5 Hz,
CHaHbCHCO), 1.28 (3H, t, JZ7.0 Hz, MeCH2), 1.16 (3H,
s, Me2C), 1.09 (3H, s, Me2C); dC (100.6 MHz, CDCl3)
192.9, 174.8, 171.0, 100.8, 80.3, 77.9, 65.1, 43.7, 36.8, 27.5,
21.1, 20.5, 14.5; HRMS (EI): MC, found 208.2967.
C13H20O2 requires 208.1464.
3.1.18. 6-((E)-but-2-enyl)-3-ethoxy-5,5-dimethylcyclo-
hex-2-enone 5a. (0.76 g, 49%) as a colourless oil; nmax
(neat) 3020, 2942, 1735, 1632, 1592, 1453, 1112 cmK1; dH
(400 MHz, CDCl3) 5.30–5.60 (2H, m, MeCH]CH), 5.19
(1H, s, ]CHCO), 3.81 (2H, q, JZ7.1 Hz, MeCH2O), 2.29
(1H, dd, JZ4.6, 17.6 Hz, CHCO), 2.14–2.17 (2H, m,
]CHCH2CHCO), 2.11 (1H, d, JZ3.5 Hz, CHaHbCMe2),
1.93–2.03 (1H, m, CHaHbCMe2), 1.53–1.64 (3H, m,
MeCH]), 1.29 (3H, t, JZ7.0 Hz, MeCH2O), 1.02 (3H, s,
Me2C), 0.91 (3H, s, Me2C); dC (100.6 MHz, CDCl3) 202.2,
174.6, 130.4, 126.2, 101.2, 64.4, 57.8, 42.3, 35.5, 30.1, 29.2,
3.1.14. 6-Allyl-3-ethoxy-5,5-dimethyl-cyclohex-2-enone
4e. (1.24 g, 75%) as a colourless oil; nmax (neat) 3019,
2960, 1740, 1640, 1598, 1456, 1372 cmK1; dH (400 MHz,
CDCl3) 5.76–5.87 (1H, m, CH]CH2), 5.21 (1H, s,

¨
C. Tanyeli, D. Ozdemirhan / Tetrahedron 61 (2005) 8212–8217
8217
24.9, 18.3, 14.5; HRMS (EI): MHC, found 223.1703.
C14H22O2 requires 223.1698.
2. (a) Li, C. J. Tetrahedron 1996, 52, 5643. (b) Chan, T. H.; Isaac,
M. B. Pure Appl. Chem. 1996, 68, 919. (c) Lubineau, A.;
Auge, J.; Queneau, Y. Synthesis 1994, 741. (d) Li, C. J. Chem.
Rev. 1993, 93, 2023. (e) Yamamato, Y.; Asao, N. Chem. Rev.
1993, 93, 2207.
3.1.19. 6-((E)-but-2-enyl)-3-methyl-cyclohex-2-enone 5b.
(0.59 g, 52%) as a colourless oil; nmax (neat) 3022, 2913,
2852, 2255, 1654, 1525 cmK1; dH (400 MHz, CDCl3) 5.78
(1H, s, ]CHCO), 5.28–5.43 (2H, m, MeCH]CH), 2.44–
2.52 (1H, m, CHCO), 2.21–2.22 (2H, m, CH2CHCO), 2.11–
2.16 (1H, m, CHaHbCH2), 1.96–2.01 (2H, m, CH2CHCO),
1.87 (3H, s, MeC]), 1.60–1.66 (1H, m, CHaHbCH2), 1.59
(3H, d, JZ6.0 Hz, MeCH]); dC (100.6 MHz, CDCl3)
201.5, 161.9, 129.0, 127.6, 126.8, 45.8, 32.8, 30.7, 27.5,
24.6, 18.3; HRMS (EI): MC, found 164.1205. C11H16O
requires 164.1202.
3. (a) Yanagisawa, A.; Habaue, S.; Yasue, K.; Yamamoto, H. J.
Am. Chem. Soc. 1994, 116, 6130. (b) Curran, D. P.; Hadida, S.;
He, M. J. Org. Chem. 1997, 62, 6714. (c) Li, C. J.; Meng, Y.;
Yi, X. H. J. Org. Chem. 1997, 62, 8632. (d) Paquette, L. A.;
Bernardelli, P. J. Org. Chem. 1997, 62, 8284. (e) Zhou, J. Y.;
Jia, Y.; Sun, G. F.; Wu, S. H. Synth. Commun. 1997, 27, 1899.
(f) Paquette, L. A.; Lobben, P. C. J. Org. Chem. 1998, 63,
6990. (g) Li, C. J.; Meng, Y.; Yi, X. H.; Ma, J.; Chan, T. H. J.
Org. Chem. 1998, 63, 7498. (h) Jacques, A.; Nadege, L. G.;
Aurelie, T. W. Tetrahedron Lett. 1999, 40, 9245.
3.2. Byproducts of the reaction
4. (a) Tsuji, J. Organic Synthesis with Palladium Compounds;
Springer: Berlin, 1981. (b) Trost, B. M. Tetrahedron 1977, 33,
2615. (c) Trost, B. M. Acc. Chem. Res. 1980, 13, 385.
5. (a) Trost, B. M.; Schmuff, N. R.; Miller, J. J. J. Am. Chem. Soc.
1980, 102, 5979. (b) Inoue, Y.; Toyofuku, M.; Hashimoto, H.
Chem. Lett. 1984, 1227. (c) Tsuji, J.; Shimizu, I.; Minami, I.;
Ohashi, Y.; Sugiura, T.; Takahashi, K. J. Org. Chem. 1985, 50,
1523. (d) Masuyama, Y.; Yamada, K.; Kurusu, Y. Tetrahedron
Lett. 1985, 28, 443. (e) Cuvigny, T.; Julia, M. J. Organomet.
Chem. 1986, 317, 383. (f) Trost, B. M. Bull. Chem. Soc. Jpn.
1988, 61, 107. (g) Breuilles, P.; Uguen, D. Tetrahedron Lett.
1990, 31, 357.
3.2.1. Dimerized product of 2a 1,10-diallyl-bicyclopentyl-
3,30-diene-2,20-dione. As a colourless oil; nmax (neat) 2990,
2973, 1707, 1690, 1589, 1437 cmK1; dH (400 MHz, CDCl3)
7.62 (2H, ddd, JZ6.7, 7.3, 10.2 Hz, 2!CH]CHCO), 6.27
(2H, d, JZ10.2 Hz, 2!]CHCO), 5.67–5.77 (2H, m, 2!
CH]CH2), 5.20 (2H, d, JZ17.2 Hz, 2!CHaHb]CH),
5.19 (2H, d, JZ10.9 Hz, 2!CHaHb]CH), 3.19 (4H, t, JZ
2.4 Hz, 2!]CHCH2), 2.82 (2H, dd, JZ7.3, 14.2 Hz, 2!
CHaHbCCO), 2.64(2H, dd, JZ6.7, 14.2 Hz, 2!CHaHbCCO);
dC (100.6 MHz, CDCl3) 203.7, 160.5, 132.5, 131.1, 120.5,
58.5, 45.5, 43.5; HRMS (EI): MC, found 242.1318. C16H18O2
requires 242.1307.
6. (a) Demir, A. S.; Jeganathan, A. Synthesis 1992, 235. (b)
Melikyan, G. G. Synthesis 1993, 833. (c) Snider, B. B. Chem.
Rev. 1996, 96, 339. (d) Melikyan, G. G. In Paquette, L. A., Ed.;
Organic Reactions; Wiley: New York, 1997; Vol. 49.
7. Williams, G. J.; Hunter, N. R. Can. J. Chem. 1976, 54, 3830.
8. (a) Tanyeli, C.; Demir, A. S.; Dikici, E. Tetrahedron:
Asymmetry 1996, 7, 2399. (b) Demir, A. S.; Hamamci, H.;
Tanyeli, C.; Akhmedov, I. M.; Doganel, F. Tetrahedron:
Asymmetry 1998, 9, 1673. (c) Demir, A. S.; Tanyeli, C.;
Altinel, E. Tetrahedron Lett. 1997, 38, 7267. (d) Tanyeli, C.;
Sezen, B. Tetrahedron Lett. 2000, 41, 7973. (e) Tanyeli, C.;
Sezen, B.; Iyigu¨n, C¸ .; Elmalı, O. Tetrahedron Lett. 2001, 42,
3.2.2. Dimerized product of 2b 1,10-diallyl-3,30-dimethyl-
bicyclopentyl-3,30-diene-2,20-dione. As a colourless oil;
nmax (neat) 3066, 2914, 2873, 1707, 1640 cmK1; dH
(400 MHz, CDCl3) 7.21 (2H, dd, JZ6.8, 7.3 Hz, 2!
]CHCO), 5.66–5.76 (2H, m, 2!CH]CH2), 5.19 (2H, d,
JZ16.6 Hz, 2!CHaHb]CH), 5.17 (2H, d, JZ10.9 Hz,
2!CHaHb]CH), 3.05 (4H, t, JZ2.2 Hz, 2!]CHCH2),
2.82 (2H, dd, JZ7.3, 14.2 Hz, 2!CHaHbCCO), 2.62 (2H,
dd, JZ6.8, 14.2 Hz, 2!CHaHbCCO), 1.86 (6H, s, 2!
MeC]); dC (100.6 MHz, CDCl3) 203.8, 153.8, 139.1,
132.7, 120.3, 59.3, 43.8, 43.6, 11.1; HRMS (EI): MC, found
270.1611. C18H22O2 requires 270.1620.
¨
6397. (f) Tanyeli, C.; Ozdemirhan, D. Tetrahedron Lett. 2002,
43, 3977. (g) Tanyeli, C.; Tosun, A.; Turkut, E.; Sezen, B.
Tetrahedron 2003, 59, 1055.
9. For spectroscopic data of 5-acetoxy-3-methyl-2-cyclo-
pentenone, see reference 8g.
Acknowledgements
10. The dimerized allylated products of 2a, 2b and 2c were
isolated in 7, 5 and 7% yields, respectively. For the dimerized
product of 2c, see Ref. 8f. The structure elucidation of
dimerized products 2a and 2b is given in Section 3.
11. We repeated the experiments for entries 1–3 with toluene
under the same conditions and obtained 2a, 2b and 2c with 5, 7
and 5% decrease of the yield, respectively.
We thank the Middle East Technical University for the
grants (no. BAP-2003-07-02-00-93) and the Turkish
Scientific and Technical Research Council for a grant [no.
TBAG-2244(102T169)] and the Turkish State Planning
Organization for a grant (no. BAP-07-02-DPT-2002
K120540-04).
12. Chaiez, G.; Chau, F.; Blanchot, B. In Martin, S. F., Ed.;
Organic Syntheses; Wiley: New York, 1999; Vol. 76, p 239.
13. Snider, B. B.; Kiselgof, E. Y. Tetrahedron 1996, 52, 6073.
14. Vinogradov, M. G.; Verenchikov, S. P.; Federova, T. M.;
Nikishin, G. I. Zh. Org. Khim. 1975, 11, 947.
References and notes
1. Trost, B. M. Science 1985, 227, 908.