Au-catalyzed tandem cyclization/[1,2]-alkyl migration reaction of epoxy alkynes: Synthesis of spiropyranones

Article abstract of DOI:10.1002/chem.200800194

A novel gold-catalyzed tandem cyclization/[1,2]-alkyl migration process of epoxy alkynes to spiropyranones has been discovered. From this process, the construction of adjacent multiple stereocenters with a new quaternary carbon atom is achieved. The gold-catalyzed domino process is stereospecific with respect to the migrating carbon atom. A type of unusual C-C bond cleavage of epoxide systems has also been discovered, which can lead to the formation of two Z alkenes and a carbonyl functional group in one step with excellent stereoselectivity. Furthermore, this efficient domino process could be achieved in the presence of the simplest and least expensive gold catalyst [NaAuCl ₄]·2H₂O with a low catalyst loading.

Full text of DOI:10.1002/chem.200800194

DOI: 10.1002/chem.200800194
Au-Catalyzed Tandem Cyclization/[1,2]-Alkyl Migration Reaction of Epoxy
G
Alkynes: Synthesis of Spiropyranones
Xing-Zhong Shu,[a] Xue-Yuan Liu,[a] Ke-Gong Ji,[a] Hui-Quan Xiao,[a] and
Yong-Min Liang*[a,b]
À
Abstract: Anovel gold-catalyzed
tandem cyclization/[1,2]-alkyl migration
ing carbon atom. Atype of unusual C
C bond cleavage of epoxide systems
has also been discovered, which can
lead to the formation of two Z alkenes
and a carbonyl functional group in one
step with excellent stereoselectivity.
Furthermore, this efficient domino pro-
cess could be achieved in the presence
of the simplest and least expensive
gold catalyst [NaAuCl4]·2H2O with a
low catalyst loading.
ACHTREUNG
process of epoxy alkynes to spiropyra-
nones has been discovered. From this
process, the construction of adjacent
multiple stereocenters with a new qua-
ternary carbon atom is achieved. The
gold-catalyzed domino process is ste-
reospecific with respect to the migrat-
Keywords: epoxy alkynes · gold ·
migration · rearrangement · spiro-
pyrane
Introduction
kynes and epoxides might be perfect intermediates in a
domino process.[9] We hypothesize that gold-activated epoxy
alkynes may undergo an anti-endo-dig cyclization to afford
the intermediate oxonium ions, which might induce the mi-
gration of neighboring groups when assisted with the hy-
droxy group (Scheme 1). Herein, we report a novel gold-cat-
In the field of organic synthesis, it is very desirable to facili-
tate two- or multistep bond formations in one pot with a
single catalyst to achieve economically useful transforma-
tions.[1] One of the most effective ways of achieving this syn-
thetic efficiency is to implement tandem reactions.[2] Recent-
ly, Au catalysis has elicited new excitement in this active
research area, and a number of consecutive C X (X=het-
eroatom) and C C bond-forming processes have been effec-
alyzed tandem cyclization/[1,2]-alky migration process to
A
[3]
spiropyranones. In this reaction, the [1,2]-migration of the
alkyl groups was a key step and the construction of adjacent
multiple stereocenters with a new quaternary carbon atom
was also achieved.
À
À
A
tive.[4] In this context, tandem cyclization/migration reac-
tions would present a valuable opportunity.[5] Although,
much attention has been paid to ether[5a,c] and carbonyl
groups,[6] other functional groups, such as aziridines and ep-
oxides, which are among the most versatile intermediates in
organic synthesis,[7] have not been explored until now.
In the context of our ongoing efforts to develop tandem
reactions,[8] we found that oxonium ions formed from al-
Scheme 1. The hypothesized activation of epoxy alkynes with gold.
[a] Dr. X.-Z. Shu, X.-Y. Liu, K.-G. Ji, H.-Q. Xiao, Prof. Y.-M. Liang
State Key Laboratory of Applied Organic Chemistry
Lanzhou University, Lanzhou 730000 (P.R. China)
Fax : (+86)931-891-2582
Results and Discussion
E-mail: liangym@lzu.edu.cn
[b] Prof. Y.-M. Liang
Optimization studies of this transformation began with
epoxy alkyne 1a (Table 1), which was readily prepared from
the corresponding enone in two steps.[10] The cyclization of
1a proceeded effectively with [NaAuCl4]·2H2O (5 mol%) in
State Key Laboratory of Solid Lubrication
Lanzhou Institute of Chemical Physics
Chinese Academy of Science, Lanzhou 730000 (P.R. China)
Supporting information for this article is available on the WWW
under http://www.chemeurj.org or from the author.
toluene at 808C and gave the expected 4(2H)-pyranone 2a
A
5282
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Chem. Eur. J. 2008, 14, 5282 – 5289

FULL PAPER
Table 1. Optimization of the reaction conditions for the cyclization of
To briefly examine the proposed proto-demetalation step
to set the gold catalyst free, under the standard conditions
ether 1l was subjected to an excess of D2O as an additive,
and the desired incorporation of the deuterium atom into 4-
1a.[a]
(2H)-pyranone 2l at C5 was observed. This result is consis-
tent with our proposed mechanism (Scheme 3), in which
proto-demetalation at C5 is believed to be the final step.
Additionally, the gold-catalyzed domino process is stereo-
specific with respect to the migrating carbon atom
(Scheme 2). The methyl-substituted compounds 1m,[12] and
1n–1p reacted smoothly to afford the only isomer of spiro-
pyranones 2m[13] and 2n in moderate yields. Better results
were obtained when the alcohols were protected with trime-
thylsilylether. We think the rearrangement proceeded via
the oxonium ion as the intermediate M, although no direct
experimental proof exists.
Entry
Catalyst
Catalyst loading
[mol%]
Solvent
Yield [%][b]
AHCTREUNG
1
2
3
4
5
6
7
8
9
10
11
12
13
A
5
5
5
5
5, 15
5, 5
5
5
5
5
5
2
1
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
xylene
n-hexane
benzene
benzene
benzene
80
52
71
C
AuCl3
AuCl
AuCl3, AgSbF6
AuCl, AgSbF
67
trace
trace
56
48
72
46
93
92
83
6
PtCl2
[Pd
[NaAuCl4]·2H2O
[NaAuCl4]·2H2O
[NaAuCl4]·2H2O
[NaAuCl4]·2H2O
[NaAuCl4]·2H2O
A
E
E
G
N
N
[a] Reactions conditions: 1a (0.3 mmol), solvent (2 mL), 808C, 12 h.
[b] Yield of isolated product.
in 80% yield after 12 h (Table 1, entry 1). With other gold
catalysts, such as [HAuCl4]·4H2O, AuCl3, and AuCl, no su-
perior results were obtained (Table 1, entries 2–4). The addi-
tion of a silver salt led to a dramatic decomposition of the
starting material (Table 1, entries 5 and 6). PtCl2 and [Pd-
Scheme 2. Stereospecific study of the gold-catalyzed domino process.
A
lytic activity, whereas moderate yields were obtained
(Table 1, entries 7 and 8). On the other hand, an excellent
yield of 2a was obtained by switching the solvent to benzene
(Table 1, entry 11).[11] Asimilar result was also achieved
when 2 mol% of [NaAuCl4]·2H2O was used (Table 1,
entry 12).
With these optimal conditions in hand, we examined the
scope of this reaction (Table 2). Various aryl groups and
alkyl substituent on the oxirane ring were tolerated
(Table 2, entries 1–4 and 11). An electron-withdrawing aryl
group gave a better result relative to electron-rich groups
(Table 2, entries 2 versus 3 and 4), which might be ascribed
to the intermediate oxonium ions (Scheme 1). After being
stabilized effectively, the ability of oxonium ions to induce
the migration of an adjacent group will be decreased. Al-
kynes with different aryl groups were compatible with this
reaction (Table 2, entries 5 and 6). If aliphatic and hetero-
aromatic alkynes were used, the reaction proceeds much
faster to afford higher yields of the desired products
(Table 2, entries 7 and 8). On the other hand, the reaction
efficiency was consistent with the ring strain. Larger-mem-
bered ring systems gave higher yields of corresponding
products in a shorter time (Table 2, entries 9–11). If the hy-
droxy group was protected with trimethylsilylether, then the
reaction proceeded efficiently in the presence of three
equivalents of H2O and gave a superior result to tertiary al-
cohol 1a (Table 2, entry 12 versus 1).
Scheme 3. Proposed mechanism for the gold-catalyzed reactions to form
2 and 4.
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5283

Y.-M. Liang et al.
Table 2. Gold-catalyzed tandem reactions of various epoxy alkynes.[a]
On the basis of the above re-
sults, a plausible mechanism for
this transformation is proposed
in Scheme 3.[18] The coordina-
tion of the gold center to epoxy
alkynes afforded complexes A
and D. The subsequent nucleo-
philic attack of the epoxide on
the alkynyl moiety leads to the
formation of intermediates B
Entry
1
Substrate
R
t [h]
Product
Yield[b] [%]
92
1a
12
2a
and E. The oxonium ion[19]
B
might trigger the [1,2]-migra-
tion of an adjacent group, when
assisted by the hydroxy group,
to give C which underwent pro-
tonation to regenerate the gold
2
3
4
1b
1c
1d
p-ClC6H4
p-CH3C6H4
m-CH3C6H4
12
12
36
2b
2c
2d
84
75
63
catalyst and produce
4(2H)-
A
pyranone 2. However, with
more difficult migration sys-
tems, such as acyclic com-
5
6
7
8
1e
1 f
1g
1h
p-ClC6H4
p-CH3C6H4
n-C5H11
7
10
4
2e
2 f
2g
2h
75
85
97
95
2-thienyl
6
pounds, the oxonium ion E in-
1
À
duced the cleavage of the C
2
3
1
À
C and C O bonds instead of
the migration process, which
leads to the formation of alken-
yl ethers 4.
9
1i
2
2i
75
85
44
10
1j
1k
20 min
2j
2k
Conclusion
We have developed an efficient
approach to spiropyranones by
11[c]
12
utilizing
tandem
a
gold-catalyzed
cyclization/[1,2]-alkyl
AHCTREUNG
migration reaction of epoxy al-
kynes, which were readily pre-
pared from the corresponding
enones in two steps. In this re-
action, the construction of adja-
cent multiple stereocenters with
a new quaternary carbon atom
was achieved. Furthermore, the
gold-catalyzed domino process
is stereospecific with respect to
12[d]
13[e]
3
6
2a
2l
90
73
1l
[a] Unless noted, all the reactions were carried out using 1 (0.3 mmol) with [NaAuCl4]·2H2O (2 mol%) in ben-
zene (2.0 mL) at 808C. [b] Yield of the isolated product. [c] Reaction run with AuCl3 (2 mol%). [d] Addition
of H2O (3 equiv). [e] Reaction was carried out in benzene/D2O (10:1).
À
Interestingly, a type of novel C C bond cleavage of epox-
ides was discovered when acyclic systems were introduced
under standard conditions (Table 3).[14] Two Z alkenes and a
carbonyl functional group were formed in one step with ex-
cellent stereoselectivity from this process. For example, com-
pounds 3a and 3b underwent the domino process to give
the corresponding products efficiently (Table 3, entries 1
the migrating carbon atom. On the other hand, the stable,
simplest, and least expensive gold catalyst [NaAuCl4]·2H2O
shows excellent catalytic activity in the reaction with low
catalyst loading. When acyclic epoxide systems were intro-
À
duced under the standard conditions, a type of unusual C C
bond cleavage of epoxy alkynes were also discovered. In
this process, two Z alkenes and a carbonyl functional group
were obtained in one step with excellent stereoselectivity.
and 2). And the syn/anti mixtures of 3c led to the products
4c in a 3:1 ratio (Table 3, entry 3).
[15]
À
Moreover, no desired
The same C C bond cleavage was also observed when an a-
product was observed when substrate 3d was employed to
hydroxy epoxide was used under the optimum conditions.
study the semipinacol rearrangement[16] under the optimal
À
conditions, whereas the same C C bond cleavage was ob-
served (Table 3, entry 4).[17]
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Chem. Eur. J. 2008, 14, 5282 – 5289

Gold Activation of Epoxy Alkynes
FULL PAPER
[a]
À
Table 3. Gold-catalyzed novel C C bond cleavage of the epoxy alkynes.
2-(3-Methylphenyl)-4-(2-phenylethyn-
yl)-1-oxaspiro[2.5]oct-4-ol (1d): Oil;
N
Entry
Substrate[b]
t [h]
Product
Yield[c] [%]
86
1H NMR (400 MHz, CDCl3): d=7.48–
7.46 (m, 2H), 7.31–7.29 (m, 3H), 7.25–
7.21 (m, 1H), 7.13–7.08 (m, 3H), 4.57
(s, 1H), 2.71 ( s, 1H), 2.35 (s, 3H),
2.25–2.18 (m, 1H), 1.91–1.70 (m, 4H),
1.57–1.49 ppm (m, 3H); 13C NMR
(100 MHz, CDCl3): d=137.7, 135.1,
131.7, 128.5, 128.2, 127.9, 126.9, 123.3,
122.4, 109.7, 88.8, 86.2, 69.6, 68.0, 60.3,
39.8, 25.3, 23.1, 23.0, 21.4 ppm; IR
(neat): n˜ =3452, 2937, 2860, 1606,
1489, 1443, 1085, 757 cmÀ1; elemental
1
3a
3b
3
4a
4b
2
3
96
3
4
3c[d]
3d
3
8
4c[e]
4d
75
62
analysis (%) calcd for C22H22O2:
C
82.99, H 6.96; found: C 83.09, H 6.87.
4-[2-(4-Chlorophenyl)ethynyl]-2-
phenyl-1-oxaspiro
Solid; m.p. 105–1078C;
A
(1e):
[a] All reactions were carried out using 3 (0.3 mmol) with NaAuCl4·2H2O (2 mol%) in benzene (2.0 mL) at
808C. [b] Ref. [15]. [c] Yield of the isolated product. [d] Syn/anti mixtures (2:1) of the substrates were used
and the ratio was determined by 1H NMR spectroscopic analysis. [e] Z/E mixtures (3:1) of the products were
obtained.
1H NMR
(300 MHz, CDCl3): d=7.40–7.25 (m,
9H), 4.58 (s, 1H), 2.74 (s, 1H), 2.22–
2.17 (m, 1H), 1.93–1.63 (m, 4H), 1.56–
1.48 ppm (m, 3H); 13C NMR (75 MHz,
CDCl3): d=135.0, 134.6, 133.0, 128.6,
Experimental Section
128.1, 127.5, 126.2, 120.8, 89.7, 85.1, 69.6, 68.0, 60.3, 39.8, 25.3, 23.1,
22.9 ppm; IR (KBr): n˜ =3448, 2939, 1490, 1448, 1088, 829, 755 cmÀ1; ele-
mental analysis (%) calcd for C21H19ClO2: C 74.44, H 5.65; found: C
74.52, H 5.69.
General: Column chromatography was carried out on silica gel. Unless
noted, the 1H NMR spectra were recorded at 300 or 400 MHz in CDCl3
and the 13C NMR spectra were recorded at 75 or 100 MHz in CDCl3 with
trimethylsilane (TMS) as an internal standard. IR spectra were recorded
on a FT-IR spectrometer, and only the major peaks are reported (in
cmÀ1). Melting points were determined on a microscopic apparatus and
are uncorrected. All new compounds were further characterized by ele-
4-[2-(4-Methylphenyl)ethynyl]-2-phenyl-1-oxaspiro
A
(1 f):
solid; m.p. 116–1188C; 1H NMR (400 MHz, CDCl3): d=7.37–7.25 (m,
7H), 7.13–7.11 (m, 2H), 4.59 (s, 1H), 2.56 (s, 1H), 2.35 (s, 3H), 2.24–2.19
(m, 1H), 1.89–1.69 (m, 4H), 1.56–1.45 ppm (m, 3H); 13C NMR
(100 MHz, CDCl3): d=138.7, 135.3, 131.7, 129.0, 128.0, 127.4, 126.3,
119.3, 87.9, 86.5, 69.6, 68.1, 60.3, 39.9, 25.4, 23.1, 23.0, 21.4 ppm; IR
(KBr): n˜ =3430, 2948, 1505, 1447, 1387, 990, 816 cmÀ1; elemental analysis
(%) calcd for C22H22O2: C 82.99, H 6.96; found: C 82.85, H 7.02.
1
ment analysis; copies of their H and 13C NMR spectra are provided. De-
tailed data of the 1H NMR NOE interaction experiments of 2m and X-
ray crystallographic studies of 1m are also provided. Commercially avail-
able reagents and solvents were used without further purification. THF
was distilled immediately before use from Na/benzophenone.
4-(Hept-1-ynyl)-2-phenyl-1-oxaspiro
[2.5]oct-4-ol (1g): Oil; 1H NMR
U
(300 MHz, CDCl3): d=7.37–7.21 (m, 5H), 4.51 (s, 1H), 2.53 (s, 1H),
2.28–2.23 (m, 2H), 2.10–2.05 (m, 1H), 1.80–1.29 (m, 13H), 0.91–0.87 ppm
(m, 3H); 13C NMR (75 MHz, CDCl3): d=135.4, 127.9, 127.3, 126.2, 87.0,
79.8, 69.0, 68.2, 60.1, 40.0, 30.9, 28.2, 25.3, 23.1, 23.0, 22.1, 18.6, 13.9 ppm;
IR (neat): n˜ =3463, 2934, 2862, 1449, 1084, 701 cmÀ1; elemental analysis
(%) calcd for C20H26O2: C 80.50, H 8.78; found: C 80.66, H 8.67.
Materials: The known E enones, as substrates 1a–1i,[20] 1l–1p,[20] 3d,[20]
1j,[21] and 1k[22] were prepared according to previous methods. Epoxy al-
kynes 1a–1k, 1m, 1o, and 3a–3c and epoxide 3d were prepared accord-
ing to previous methods.[8d]
2-Phenyl-4-(2-phenylethynyl)-1-oxaspiro
A
(1a):
Solid;
m.p. 90–928C; 1H NMR (400 MHz, CDCl3): d=7.48–7.46 (m, 2H), 7.37–
7.25 (m, 8H), 4.59 (s, 1H), 2.57 (s, 1H), 2.25–2.21 (m, 1H), 1.91–1.69 (m,
4H), 1.57–1.46 ppm (m, 3H); 13C NMR (100 MHz, CDCl3) d=135.2,
131.8, 128.6, 128.3, 128.1, 127.5, 126.3, 122.4, 88.7, 86.3, 69.6, 68.1, 60.3,
39.9, 25.4, 23.1, 23.0 ppm; IR (KBr): n˜ =3435, 2948, 1666, 1621, 1449, 993,
756 cmÀ1; elemental analysis (%) calcd for C21H20O2: C 82.86, H 6.62;
found: C 82.89, H 6.54.
2-Phenyl-4-[2-(thienyl)ethynyl]-1-oxaspiro
A
(1h):
Oil;
1H NMR (300 MHz, CDCl3): d=7.40–7.23 (m, 7H), 6.99–6.96 (m, 1H),
4.57 (s, 1H), 2.59 (s, 1H), 2.23–2.17 (m, 1H), 1.91–1.63 (m, 4H), 1.59–
1.46 ppm (m, 3H); 13C NMR (75 MHz, CDCl3) d=135.1, 132.5, 128.1,
127.5, 127.4, 126.9, 126.3, 122.2, 92.5, 79.6, 69.8, 67.9, 60.3, 39.7, 25.3, 23.1,
22.9 ppm; IR (neat): n˜ =3449, 2938, 2860, 1773, 1447, 1193, 1084,
702 cmÀ1; elemental analysis (%) calcd for C19H18O2S: C 73.52, H 5.84;
found: C 73.64, H 5.89.
2-(4-Chlorophenyl)-4-(2-phenylethynyl)-1-oxaspiro
A
(1b):
Solid; m.p. 122–1248C; 1H NMR (400 MHz, CDCl3): d=7.47–7.45 (m,
2H), 7.33–7.31 (m, 5H), 7.26–7.24 (m, 2H), 4.56 (s, 1H), 2.64 (s, 1H),
2.22–2.19 (m, 1H), 1.90–1.67 (m, 4H), 1.55–1.43 ppm (m, 3H); 13C NMR
(100 MHz, CDCl3): d=133.8, 133.3, 131.7, 128.6, 128.3, 127.7, 122.3, 88.5,
86.4, 69.6, 68.2, 59.7, 39.8, 25.3, 23.1, 22.9 ppm; IR (KBr): n˜ =3453, 2938,
2-Phenyl-4-(2-phenylethynyl)-1-oxaspiro
N
(1i):
Solid;
m.p. 41–438C; 1H NMR (300 MHz, CDCl3): d=7.49–7.44 (m, 2H), 7.39–
7.24 (m, 8H), 4.49 (s, 1H), 3.33 (s, 1H), 2.34–2.26 (m, 1H), 2.18–2.10 (m,
1H), 1.78–1.58 (m, 6H), 1.52–1.42 ppm (m, 2H); 13C NMR (75 MHz,
CDCl3): d=135.2, 131.7, 128.4, 128.2, 128.2, 127.6, 126.4, 122.5, 90.7, 84.4,
71.2, 69.9, 62.3, 42.2, 29.7, 24.4, 23.7, 22.2 ppm; IR (KBr): n˜ =3456, 2940,
2361, 1447, 1150, 754 cmÀ1; elemental analysis (%) calcd for C22H22O2: C
82.99, H 6.96; found: C 83.06, H 6.88.
2859, 1492, 1443, 1088, 757 cmÀ1
C21H19ClO2: C 74.44, H 5.65; found: C 74.52, H 5.48.
; elemental analysis (%) calcd for
2-(4-Methylphenyl)-4-(2-phenylethynyl)-1-oxaspiro
A
(1c):
1
Solid; m.p. 76–778C; H NMR (300 MHz, CDCl3): d=7.48–7.44 (m, 2H),
7.31–7.29 (m, 3H), 7.23–7.20 (d, J=7.5 Hz, 2H), 7.16–7.13 (d, J=7.5 Hz,
2H), 4.58 (s, 1H), 2.77 (s, 1H), 2.33 (s, 3H), 2.26–2.18 (m, 1H), 1.93–1.67
(m, 4H), 1.55–1.48 ppm (m, 3H); 13C NMR (75 MHz, CDCl3): d=137.0,
132.1, 131.7, 128.7, 128.4, 128.2, 126.2, 122.4, 88.8, 86.2, 69.6, 68.0, 60.2,
39.8, 25.3, 23.1, 22.9, 21.1 ppm; IR (KBr): n˜ =3455, 2938, 2860, 2247,
1828, 1443, 1086, 758 cmÀ1; elemental analysis (%) calcd for C22H22O2: C
82.99, H 6.96; found: C 82.86, H 6.92.
2-Phenyl-4-(2-phenylethynyl)-1-oxaspiro
(1j):
Solid;
m.p. 83–858C; 1H NMR (300 MHz, CDCl3): d=7.46–7.43 (m, 2H), 7.41–
7.24 (m, 8H), 4.60 (s, 1H), 2.98 (s, 1H), 2.25–2.16 (m, 2H), 1.82–1.61 (m,
7H), 1.42–1.39 (m, 2H), 1.29–1.26 ppm (m, 1H); 13C NMR (75 MHz,
CDCl3): d=135.6, 131.8, 128.4, 128.2, 128.2, 127.6, 126.3, 122.5, 90.3, 84.5,
71.7, 68.5, 63.9, 35.0, 25.6, 24.4, 24.0, 24.0, 22.1 ppm; IR (KBr): n˜ =3474,
2918, 2865, 1491, 1446, 1117, 764, 696 cmÀ1; elemental analysis (%) calcd
for C23H24O2: C 83.10, H 7.28; found: C 83.24; 7.22.
Chem. Eur. J. 2008, 14, 5282 – 5289
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5285

Y.-M. Liang et al.
2-Isopropyl-4-(2-phenylethynyl)-1-oxaspiro
G
3-Phenyl-1-(3-phenyloxiran-2-yl)prop-2-yn-1-ol (3c) (2:1 mixture of syn/
anti diastereoisomers): Oil; 1H NMR (300 MHz, CDCl3, 2:1 mixture of
diastereoisomers): d=7.46–7.43 (m, 2H), 7.37–7.23 (m, 8H), [4.96–4.94
(m), 4.77–4.73 (m), 1 H], [4.14–4.13 (d, J=2.4 Hz), 4.04–4.03 (d, J=
2.4 Hz), 1 H], 3.43–3.40 (m, 1H), 2.88–2.86 ppm (m, 1H); 13C NMR
(75 MHz, CDCl3, 2:1 mixture of diastereoisomers) d=136.1, 135.9, 131.8,
128.7, 128.5, 128.4, 128.2, 125.9, 121.9, 86.7, 85.9, 85.1, 64.0, 63.3, 62.1,
61.5, 56.2, 55.9 ppm; IR (neat): n˜ =3430, 3060, 2923, 2230, 1638, 1491,
1265, 1032 cmÀ1; elemental analysis (%) calcd for C17H14O2: C 81.58, H
5.64; found: C 81.43, H 5.77.
m.p. 71–738C; 1H NMR (300 MHz, CDCl3): d=7.42–7.39 (m, 2H), 7.31–
7.26 (m, 3H), 3.03–2.99 (m, 1H), 2.81 (s, 1H), 2.26–1.95 (m, 4H), 1.86–
1.78 (m, 2H), 1.50–1.42 (m, 1H,) 1.14–1.10 (m, 3H), 1.04–1.00 ppm (m,
3H); 13C NMR (75 MHz, CDCl3): d=131.6, 128.3, 128.2, 122.6, 89.6, 85.0,
72.8, 67.5, 41.0, 29.1, 26.6, 20.2, 19.8, 18.3 ppm; IR (KBr): n˜ =3490, 2963,
1485, 1061, 760 cmÀ1; elemental analysis (%) calcd for C17H20O2: C 79.65,
H 7.86; found: C 79.73, H 7.72.
2-Phenyl-4-(2-phenylethynyl)-4-trimethylsiloxy-1-oxaspiro[2.5]octane
(1l): Oil; 1H NMR (300 MHz, CDCl3): d=7.48–7.45 (m, 2H), 7.36–7.26
(m, 8H), 4.49 (s, 1H), 2.12–2.08 (m, 1H), 2.04–1.96 (m, 1H), 1.78–1.65
(m, 3H), 1.61–1.48 (m, 2H), 1.36–1.31 (m, 1H), 0.32–0.30 ppm (m, 9H);
13C NMR (75 MHz, CDCl3): d=136.0, 131.5, 128.5, 128.4, 127.9, 127.2,
126.3, 122.6, 90.1, 87.0, 72.1, 68.0, 60.3, 40.8, 25.0, 23.5, 21.8, 1.88 ppm; IR
(neat): n˜ =2944, 2860, 1447, 1252, 1110, 1033, 910, 843, 755, 696 cmÀ1; ele-
mental analysis (%) calcd for C24H28O2Si: C 76.55, H 7.49; found: C
76.62, H 7.53.
2,4-Diphenyl-1-oxaspiro[2.5]oct-4-ol (3d): Solid; m.p. 119–1208C;
G
1H NMR (300 MHz, CDCl3): d=7.61–7.58 (m, 2H), 7.44–7.29 (m, 8H),
4.56 (s, 1H), 2.68–2.61 (m, 1H), 2.50 (s, 1H), 1.93–1.84 (m, 1H), 1.80–
1.74 (m, 1H), 1.65–1.32 ppm (m, 5H); 13C NMR (75 MHz, CDCl3): d=
140.7, 135.4, 128.6, 128.2, 128.0, 127.6, 127.3, 126.3, 74.1, 68.5, 61.0, 38.4,
25.7, 23.6, 23.1 ppm; IR (KBr): n˜ =3467, 2938, 2862, 1495, 1449, 1077,
755, 699 cmÀ1; elemental analysis (%) calcd for C19H20O2: C 81.40, H
7.19; found: C 81.27, H 7.36.
5-Methyl-2-phenyl-4-(2-phenylethynyl)-1-oxaspiro
1
General procedure for the preparation of spiropyranones 2a–2n,ethers
4a–4c,and ketone 4d : [NaAuCl4]·2H2O (2.37 mg, 2 mol%) was added to
a stirred solution of epoxide (0.30 mmol) in benzene (2.0 mL) under air
at 808C. When the reaction was considered to be complete, as deter-
mined by TLC analysis, the reaction mixture was diluted with ethyl ace-
tate (10 mL) and evaporated under reduced pressure. The residue was
purified by chromatography on silica gel to afford the corresponding
products.
Solid; m.p. 90–928C; H NMR (300 MHz, CDCl3): d=7.50–7.44 (m, 2H),
7.38–7.23 (m, 8H), 4.59 (s, 1H), 2.39 (s, 1H), 1.91–1.80 (m, 2H), 1.75–
1.72 (m, 1H), 1.65–1.47 (m, 3H), 1.36–1.21 ppm (m, 4H); 13C NMR
(75 MHz, CDCl3): d=135.4, 131.8, 128.5, 128.2, 128.0, 127.4, 126.2, 122.5,
87.4, 86.6, 73.0, 68.4, 59.5, 42.8, 31.8, 25.8, 22.5, 16.1 ppm; IR (KBr): n˜ =
3428, 2931, 2863, 1450, 1078, 750 cmÀ1; elemental analysis (%) calcd for
C22H22O2: C 82.99, H 6.96; found: C 82.86, H 6.88.
2-Phenyl-4-(2-phenylethynyl)-5-methyl-4-trimethylsiloxy-1-oxaspiro-
6,8-Diphenyl-7-oxaspiro
ACHTREUNG
A
above method in 92% yield as
a
2H), 7.40–7.26 (m, 8H), 4.45 (s, 1H), 2.15–2.09 (m, 1H), 1.81–1.70 (m,
2H), 1.61–1.54 (m, 3H), 1.49–1.39 (m, 1H), 1.19–1.17 (d, J=6.6 Hz, 3H),
0.34 ppm (s, 9H); 13C NMR (75 MHz, CDCl3): d=136.2, 131.4, 128.6,
128.4, 128.0, 127.3, 126.2, 122.5, 89.2, 88.5, 75.5, 68.1, 60.0, 42.2, 30.6, 25.6,
21.8, 16.4, 2.19 ppm; IR (neat): n˜ =3405, 2936, 1449, 1252, 1108, 843,
753 cmÀ1; elemental analysis (%) calcd for C25H30O2Si: C 76.88, H 7.74;
found: C 76.95, H 7.79.
(300 MHz, CDCl3): d=7.76–7.73 (m, 2H), 7.50–7.25 (m, 8H), 6.06 (s,
1H), 5.42 (s, 1H), 2.30–2.19 (m, 1H), 1.98–1.88 (m, 1H), 1.81–1.48 (m,
4H), 1.32–1.22 (m, 1H), 1.17–1.06 ppm (m, 1H); 13C NMR (75 MHz,
CDCl3): d=198.7, 168.3, 136.0, 132.6, 131.4, 128.5, 128.5, 128.3, 128.1,
126.4, 100.4, 87.0, 54.9, 31.4, 30.1, 26.0, 25.9 ppm; IR (KBr): n˜ =3434,
2943, 2862, 1660, 1607, 1362, 1040, 696 cmÀ1; elemental analysis (%)
calcd for C21H20O2: C 82.86, H 6.62; found: C 82.98, H 6.54.
2-Isopropyl-5-methyl-4-(2-phenylethynyl)-1-oxaspiro
6-(4-Chlorophenyl)-8-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2b): Pre-
H
1
Solid; m.p. 93–958C; H NMR (300 MHz, CDCl3): d=7.46–7.42 (m, 2H),
7.32–7.26 (m, 3H), 3.14–3.11 (d, J=9.3 Hz, 1H), 2.22–2.16 (m, 2H), 1.73–
1.46 (m, 7H), 1.20–1.18 (d, J=6.6 Hz, 3H), 1.13–1.10 (d, J=6.3 Hz, 3H),
1.00–0.97 ppm (d, J=6.9 Hz, 3H); 13C NMR (75 MHz, CDCl3): d=131.8,
128.4, 128.2, 122.6, 87.1, 86.9, 72.6, 66.4, 65.0, 42.4, 31.7, 27.0, 26.3, 22.5,
20.2, 18.5, 16.2 ppm; IR (KBr): n˜ =3447, 2962, 2928, 2865, 1455, 1074,
755 cmÀ1; elemental analysis (%) calcd for C19H24O2: C 80.24, H 8.51;
found: C 80.32, H 8.45.
pared by using the above method in 84% yield as a solid. M.p. 122–
1248C; H NMR (300 MHz, CDCl3): d=7.74–7.70 (m, 2H), 7.47–7.37 (m,
1
7H), 6.05–6.03 (m, 1H), 5.40–5.38 (m, 1H), 2.26–2.20 (m, 1H), 1.85–1.55
(m, 5H), 1.33–1.14 ppm (m, 2H); 13C NMR (75 MHz, CDCl3): d=198.3,
168.1, 134.6, 134.5, 132.5, 131.5, 129.7, 128.6, 128.4, 126.4, 100.5, 86.4,
54.9, 31.6, 30.2, 26.0 ppm; IR (KBr): n˜ =2950, 2864, 1657, 1603, 1360, 828,
689 cmÀ1; elemental analysis (%) calcd for C21H19ClO2: C 74.44, H 5.65;
found: C 74.62, H 5.69.
2-Isopropyl-4-(2-phenylethynyl)-5-methyl-4-trimethylsiloxy-1-oxaspiro-
6-(4-Methylphenyl)-8-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2c): Pre-
A
A
pared by using the above method in 75% yield as a solid. M.p. 113–
2H), 7.35–7.33 (m, 3H), 3.00–2.97 (m, 1H), 2.18–2.12 (m, 1H), 2.00–1.94
(m, 1H), 1.76–1.50 (m, 6H), 1.13–1.07 (m, 6H), 1.00–0.98 (m, 3H), 0.29–
0.22 ppm (m, 9H); 13C NMR (75 MHz, CDCl3): d=131.4, 128.5, 128.4,
122.6, 89.2, 88.8, 75.2, 66.5, 65.5, 41.5, 31.2, 27.1, 26.7, 22.3, 20.3, 18.8,
1
1148C; H NMR (300 MHz, CDCl3): d=7.75–7.72 (m, 2H), 7.47–7.35 (m,
5H), 7.20–7.18 (m, 2H), 6.04 (s, 1H), 5.39 (s, 1H), 2.37 (s, 3H), 2.24–2.19
(m, 1H), 1.92–1.51 (m, 5H), 1.35–1.29 (m, 1H), 1.22–1.11 ppm (m, 1H);
13C NMR (75 MHz, CDCl3): d=198.8, 168.3, 138.3, 133.1, 132.8, 131.3,
128.8, 128.5, 128.3, 126.4, 100.4, 87.1, 55.0, 31.8, 30.2, 26.0, 21.1 ppm; IR
(KBr): n˜ =3406, 2949, 2863, 1658, 1607, 1367, 1043, 692 cmÀ1; elemental
analysis (%) calcd for C22H22O2: C 82.99, H 6.96; found: C 82.87, H 7.02.
16.6, 2.23 ppm; IR (neat): n˜ =3399, 2961, 1453, 1251, 1116, 842, 756 cmÀ1
;
elemental analysis (%) calcd for C22H32O2Si: C 74.10, H 9.05; found: C
74.23, H 9.11.
(S)-4-Phenyl-2-[(2R,3S)-3-phenyloxiran-2-yl]but-3-yn-2-ol (3a): Solid;
m.p. 74–768C; 1H NMR (300 MHz, CDCl3): d=7.46–7.42 (m, 2H), 7.35–
7.24 (m, 8H), 4.17 (m, 1H), 3.30–3.29 (m, 1H), 2.68 (s, 1H), 1.72 ppm (s,
3H); 13C NMR (75 MHz, CDCl3): d=136.3, 131.8, 128.6, 128.5, 128.4,
128.2, 125.9, 122.0, 88.3, 85.2, 67.1, 67.1, 56.7, 27.4 ppm; IR (KBr): n˜ =
3425, 2986, 1600, 1492, 1365, 1132, 1068, 899, 755, 695 cmÀ1; elemental
analysis (%) calcd for C18H16O2: C 81.79, H 6.10; found: C 81.72, H 6.19.
(S)-2-[(2R,3S)-3-Phenyloxiran-2-yl]non-3-yn-2-ol (3b): Oil; 1H NMR
(300 MHz, CDCl3): d=7.38–7.28 (m, 5H), 4.08–4.07 (d, J=1.8 Hz, 1H),
3.18–3.17 (d, J=2.4 Hz, 1H), 2.44 (s, 1H), 2.22–1.18 (m, 2H), 1.59 (s,
3H), 1.53–1.46 (m, 2H), 1.37–1.26 (m, 4H), 0.90–0.85 ppm (m, 3H);
13C NMR (75 MHz, CDCl3): d=136.5, 128.5, 128.3, 125.8, 86.2, 79.5, 67.3,
66.6, 56.6, 31.0, 28.1, 27.6, 22.1, 18.6, 13.9 ppm; IR (neat): n˜ =3444, 2929,
2862, 1719, 1459, 1369, 898, 699 cmÀ1; elemental analysis (%) calcd for
C17H22O2: C 79.03, H 8.58; found: C 79.15, H 8.51.
6-(3-Methylphenyl)-8-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2d): Pre-
A
pared by using the above method in 63% yield as a solid. M.p. 71–728C;
1H NMR (300 MHz, CDCl3): d=7.75–7.73 (d, J=6.9 Hz, 2H), 7.47–7.36
(m, 3H), 7.28–7.27 (m, 3H), 7.19–7.18 (m, 1H), 6.04 (s, 1H), 5.38 (s, 1H),
2.38–2.36 (m, 3H), 2.24–2.20 (m, 1H), 1.95–1.88 (m, 1H), 1.81–1.51 (m,
4H), 1.34–1.28 (m, 1H), 1.18–1.12 ppm (m, 1H); 13C NMR (75 MHz,
CDCl3): d=198.7, 168.3, 137.7, 136.0, 132.7, 131.3, 129.2, 129.1, 128.5,
128.0, 126.4, 125.5, 100.4, 87.2, 55.0, 31.5, 30.2, 25.9, 25.9, 21.5 ppm; IR
(KBr): n˜ =3432, 2952, 2868, 1659, 1606, 1373, 1050, 693 cmÀ1; elemental
analysis (%) calcd for C22H22O2: C 82.99, H 6.96; found: C 83.13, H 6.82.
8-(4-Chlorophenyl)-6-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2e): Pre-
G
pared by using the above method in 75% yield as a solid. M.p. 168–
1
1698C; H NMR (300 MHz, CDCl3): d=7.69–7.65 (m, 2H), 7.48–7.35 (m,
7H), 6.01 (s, 1H), 5.41 (s, 1H), 2.25–2.21 (m, 1H), 1.94–1.51 (m, 5H),
1.33–1.29 (m, 1H), 1.15–1.10 ppm (m, 1H); 13C NMR (75 MHz, CDCl3):
5286
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 5282 – 5289

d=198.5, 167.1, 137.5, 135.9, 131.1, 128.8, 128.6, 128.4, 128.2, 127.7, 100.6,
87.2, 55.0, 31.5, 30.2, 26.0 ppm; IR (KBr): n˜ =3405, 2929, 2860, 1656,
1605, 1088, 825cmÀ1; elemental analysis (%) calcd for C21H19ClO2: C
74.44, H 5.65; found: C 74.61, H 5.52.
1-Methyl-6,8-diphenyl-7-oxaspiro[4.5]dec-8-en-10-one (2m): Prepared by
G
Gold Activation of Epoxy Alkynes
FULL PAPER
using the above method in 67% yield from 1m. When substrate 1n was
used, H2O (3 equiv) was added to afford 2m in 76% yield as an oil.
1H NMR (300 MHz, CDCl3): d=7.67–7.64 (m, 2H), 7.42–7.25 (m, 8H),
6.05 (s, 1H), 5.60 (s, 1H), 2.40–2.34 (m, 1H), 2.22–2.13 (m, 1H), 1.90–
1.72 (m, 2H), 1.67–1.60 (m, 1H), 1.47–1.24 ppm (m, 5H); 13C NMR
(75 MHz, CDCl3): d=198.0, 167.0, 137.4, 133.1, 131.3, 128.9, 128.7, 128.5,
128.4, 126.5, 101.2, 84.7, 56.7, 43.7, 33.1, 30.4, 23.2, 16.1 ppm; IR (neat):
n˜ =2955, 2874, 1656, 1606, 1377, 1031, 695 cmÀ1; elemental analysis (%)
calcd for C22H22O2: C 82.99, H 6.96; found: C 82.83, H 7.08.
8-(4-Methylphenyl)-6-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2 f): Pre-
N
pared by using the above method in 85% yield as a solid. M.p. 141–
1
1428C; H NMR (300 MHz, CDCl3): d=7.65–7.62 (m, 2H), 7.48–7.46 (m,
2H), 7.41–7.36 (m, 3H), 7.21–7.18 (m, 2H), 6.02–6.01 (m, 1H), 5.40–5.39
(m, 1H), 2.37–2.36 (m, 3H), 2.26–2.21 (m, 1H), 1.94–1.50 (m, 5H), 1.26
(m, 1H), 1.12–1.08 ppm (m, 1H); 13C NMR (75 MHz, CDCl3): d=198.7,
168.5, 142.0, 136.2, 129.8, 129.3, 128.5, 128.4, 128.1, 126.4, 99.8, 87.0, 55.0,
31.5, 30.2, 26.0, 21.4 ppm; IR (KBr): n˜ =2953, 2861, 1656, 1606, 1360,
1046, 821, 706 cmÀ1; elemental analysis (%) calcd for C22H22O2: C 82.99,
H 6.96; found: C 83.06, H 6.88.
6-Isopropyl-1-methyl-8-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2n): Pre-
R
pared by using the above method in 43% yield from 1o. When substrate
1p was used, H2O (3 equiv) was added to afford 2n in 52% yield as a
solid. M.p. 68–708C; 1H NMR (300 MHz, CDCl3): d=7.78–7.75 (m, 2H),
7.48–7.27 (m, 3H), 5.89 (s, 1H), 4.51–4.49 (d, J=4.2 Hz, 1H), 2.27–2.10
(m, 3H), 1.89–1.68 (m, 3H), 1.57–1.48 (m, 1H), 1.35–1.30 (m, 1H), 1.17–
1.15 (d, J=6.9 Hz, 3H), 1.10–1.08 (d, J=7.5 Hz, 3H), 0.95–0.93 ppm (d,
J=7.2 Hz, 3H); 13C NMR (75 MHz, CDCl3): d=198.4, 167.8, 133.1,
131.2, 128.6, 126.3, 100.2, 86.8, 57.1, 43.7, 32.4, 30.9, 28.2, 23.0, 21.6, 18.5,
16.5 ppm; IR (KBr): n˜ =3301, 2961, 2875, 1658, 1608, 1456, 1385, 1341,
1043, 692cmÀ1; elemental analysis (%) calcd for C19H24O2: C 80.24, H
8.51; found: C 80.31, H 8.44.
8-Pentyl-6-phenyl-7-oxaspiro[4.5]dec-8-en-10-one (2g): Prepared by
G
using the above method in 97% yield as an oil. 1H NMR (300 MHz,
CDCl3): d=7.39–7.33 (m, 5H), 5.35 (s, 1H), 5.20 (s, 1H), 2.26–2.12 (m,
3H), 1.87–1.45 (m, 8H), 1.20–1.08 (m, 2H), 0.94–0.83 ppm (m, 6H);
13C NMR (75 MHz, CDCl3): d=198.2, 175.5, 136.2, 128.4, 128.4, 128.0,
102.6, 86.9, 54.4, 34.4, 31.9, 31.0, 30.2, 26.0, 25.9, 22.2, 13.8 ppm; IR
(neat): n˜ =3400, 2927, 2860, 1667, 1616, 1457, 1388, 1005, 704 cmÀ1; ele-
mental analysis (%) calcd for C20H26O2: C 80.50, H 8.78; found: C 80.57,
H 8.73.
(3Z)-4-Phenyl-4-(styryloxy)but-3-en-2-one (4a): Prepared by using the
above method in 86% yield as an oil. 1H NMR (300 MHz, CDCl3): d=
7.91–7.88 (m, 2H), 7.59–7.25 (m, 8H), 6.56–6.54 (d, J=6.3 Hz, 1H), 6.48
(s, 1H), 5.83–5.81 (d, J=6.9 Hz, 1H), 2.57 ppm (s, 3H); 13C NMR
(75 MHz, CDCl3): d=190.2, 170.8, 139.7, 137.9, 133.7, 132.2, 129.0, 128.5,
127.8, 127.5, 114.4, 101.2, 19.2 ppm; IR (neat): n˜ =3399, 3059, 1658, 1594,
1392, 1175, 1062, 697 cmÀ1; elemental analysis (%) calcd for C18H16O2: C
81.79, H 6.10; found: C 81.91, H 6.02.
6-Phenyl-8-(2-thienyl)-7-oxaspiro
ACHTREUNG
using the above method in 95% yield as
a
1H NMR (300 MHz, CDCl3): d=7.54–7.36 (m, 7H), 7.08–7.05 (m, 1H),
5.93 (s, 1H), 5.41 (s, 1H), 2.24–2.16 (m, 1H), 1.91–1.51 (m, 5H), 1.31–
1.26 (m, 1H), 1.17–1.11 ppm (m, 1H); 13C NMR (75 MHz, CDCl3): d=
198.1, 163.4, 136.6, 135.9, 130.0, 128.6, 128.4, 128.2, 128.1, 99.4, 87.3, 55.2,
31.9, 30.3, 26.0 ppm; IR (KBr): n˜ =3399, 2948, 2864, 1655, 1594, 1384,
1317, 707 cmÀ1; elemental analysis (%) calcd for C19H18O2S: C 73.52, H
5.84; found: C 73.63, H 5.79.
(3Z)-4-(Styryloxy)non-3-en-2-one (4b): Prepared by using the above
method in 96% yield as an oil. 1H NMR (400 MHz, CDCl3): d=7.33–
7.24 (m, 5H), 6.95–6.92 (d, J=9.0 Hz, 1H), 6.39–6.36 (d, J=9.3 Hz, 1H),
5.62 (s, 1H), 2.81–2.77 (m, 2H), 2.16 (s, 3H), 1.64–1.56 (m, 2H), 1.38–
1.34 (m, 4H), 0.94–0.84 ppm (m, 3H); 13C NMR (100 MHz, CDCl3): d=
196.4, 173.6, 139.8, 134.0, 128.7, 127.5, 126.1, 117.4, 103.4, 32.0, 31.5, 31.4,
26.8, 22.4, 13.9 ppm; IR (neat): n˜ =3454, 3058, 2930, 2862, 1684, 1588,
1380, 1152, 947 cmÀ1; elemental analysis (%) calcd for C17H22O2: C 79.03,
H 8.58; found: C 78.92, H 8.66.
1,3-Diphenyl-2-oxaspiro
ACHTREUNG
above method in 75% yield as
a
(300 MHz, CDCl3): d=7.74–7.71 (m, 2H), 7.48–7.33 (m, 8H), 5.97 (s,
1H), 5.39 (s, 1H), 2.08–2.01 (m, 1H), 1.95–1.91 (m, 1H), 1.82–1.78 (m,
1H), 1.57–1.51 (m, 2H), 1.43–1.22 (m, 4H), 1.07 ppm (m, 1H); 13C NMR
(75 MHz, CDCl3): d=200.0, 167.3, 135.6, 132.5, 131.3, 128.7, 128.6, 128.5,
128.1, 126.4, 100.6, 88.5, 46.2, 30.6, 26.7, 25.6, 22.3, 21.3 ppm; IR (KBr):
n˜ =2924, 2852, 2349, 1661, 1611, 1366, 776, 705 cmÀ1; elemental analysis
(%) calcd for C22H22O2: C 82.99, H 6.96; found: C 82.87, H 7.06.
(2Z)-3-Phenyl-3-(styryloxy)acrylaldehyde (4c): Compound 4c (3:1 of Z/E
mixtures) was prepared by using the above method in 75% yield as an
1
oil, but syn/anti mixtures (2:1) of the substrates were used: H NMR (3:1
of Z/E mixtures, 300 MHz, CDCl3): d=[10.20–10.17 (m), 9.55–9.52 (m), 1
H], 7.62–7.37 (m, 5H), 7.35–7.17 (m, 5H), [7.15–7.11 (m), 7.07–7.02 (d,
J=13.5 Hz), 1 H], [6.53–6.49 (d, J=12.3 Hz), 6.33–6.29 (d, J=12.3 Hz), 1
H], [6.02–5.99 (m), 5.88–5.85 (m), 1 H] ppm; 13C NMR (3:1 of Z/E mix-
tures, 75 MHz, CDCl3): d=191.8, 189.9, 174.2, 168.2, 144.6, 139.9, 133.9,
133.3, 132.5, 131.8, 131.6, 131.4, 129.9, 128.9, 128.7, 128.6, 128.4, 127.7,
127.5, 127.0, 126.1, 125.6, 118.4, 113.9, 113.2, 109.1 ppm; IR (neat): n˜ =
3452, 3059, 2848, 1960, 1658, 1607, 1347, 1212, 1127, 752 cmÀ1; elemental
analysis (%) calcd for C17H14O2: C 81.58, H 5.64; found: C 81.71, H 5.57.
1,3-Diphenyl-2-oxaspiro[5.6]dodec-3-en-5-one (2j): Prepared by using
A
the above method in 85% yield as a solid. M.p. 147–1498C; 1H NMR
(400 MHz, CDCl3): d=7.76–7.74 (m, 2H), 7.53–7.26 (m, 8H), 6.03 (m,
1H), 5.27 (s, 1H), 2.37–2.31 (m, 1H), 1.96–1.91 (m, 1H), 1.72–1.60 (m,
4H), 1.49–1.28 (m, 4H), 1.02–0.96 (m, 1H), 0.49–0.44 ppm (m, 1H);
13C NMR (100 MHz, CDCl3): d=199.3, 168.2, 135.9, 132.5, 131.4, 128.6,
128.4, 128.1, 126.4, 100.2, 89.3, 50.6, 31.3, 31.0, 30.5, 28.5, 23.5, 22.4 ppm;
IR (KBr): n˜ =2924, 2856, 1661, 1609, 1350, 776, 705 cmÀ1; elemental anal-
ysis (%) calcd for C23H24O2: C 83.10, H 7.28; found: C 83.19, H 7.26.
1,7-Diphenylheptane-1,6-dione (4d): Prepared by using the above
method in 62% yield as a solid. M.p. 56–578C; 1H NMR (300 MHz,
CDCl3): d=7.93–7.91 (m, 2H), 7.55–7.52 (m, 1H), 7.47–7.42 (m, 2H),
7.35–7.19 (m, 5H), 3.69 (s, 2H), 2.95–2.91 (t, J=7.2 Hz, 2H), 2.53–2.49 (t,
J=6.9 Hz, 2H), 1.69–1.62 ppm (m, 4H); 13C NMR (75 MHz, CDCl3): d=
208.1, 199.9, 136.8, 134.2, 132.9, 129.3, 128.7, 128.5, 127.9, 127.0, 50.1,
41.7, 38.2, 23.5, 23.2 ppm; IR (KBr): n˜ =3397, 2940, 1704, 1675, 1450,
1402, 1256, 696 cmÀ1; elemental analysis (%) calcd for C19H20O2: C 81.40,
H 7.19; found: C 81.49, H 7.13.
5-Isopropyl-7-phenyl-6-oxaspiro[3.5]non-7-en-9-one (2k): Prepared by
A
using the above method, but with AuCl3 as the catalyst, in 44% yield as
an oil. 1H NMR (300 MHz, CD3COCD3): d=7.61–7.57 (m, 2H), 7.39–
7.31 (m, 3H), 5.49 (s, 1H), 4.13–4.09 (d, J=9.6 Hz, 1H), 2.45–2.30 (m,
3H), 2.15–1.98 (m, 4H), 1.12–1.09 (m, 3H), 0.88–0.83 ppm (m, 3H);
13C NMR (75 MHz, CD3COCD3): d=217.3, 157.0, 131.4, 129.2, 128.9,
125.7, 101.4, 94.6, 62.6, 39.0, 38.8, 20.2, 20.1, 19.4 ppm; IR (neat): n˜ =
3452, 2962, 2871, 1735, 1641, 1450, 1045, 733 cmÀ1; elemental analysis
(%) calcd for C17H20O2: C 79.65, H 7.86; found: C 79.59, H 7.88.
[9D]6,8-Diphenyl-7-oxaspiro[4.5]dec-8-en-10-one (2l): Prepared by using
G
the above method, but using benzene/H2O (10:1 v/v) as the solvent, in
73% yield as a solid. M.p. 122–1248C; 1H NMR (300 MHz, CDCl3): d=
7.76–7.73 (m, 2H), 7.50–7.25 (m, 8H), 6.06 (s, 0.01H), 5.43 (s, 1H), 2.29–
2.22 (m, 1H), 2.19–1.89 (m, 1H), 1.82–1.50 (m, 4H), 1.32–1.26 (m, 1H),
1.17–1.06 ppm (m, 1H); IR (KBr): n˜ =2948, 2866, 1657, 1598, 1566, 1353,
Acknowledgement
1292, 697 cmÀ1
.
We thank the NSF (NSF-20621091, NSF-20672049) for financial support.
Chem. Eur. J. 2008, 14, 5282 – 5289
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Gold Activation of Epoxy Alkynes
FULL PAPER
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Received: January 31, 2008
Published online: May 7, 2008
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