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. 2018 Jun 5;14:1317–1348. doi: 10.3762/bjoc.14.113

Table 1.

Thermal cycloaddition of sydnones with symmetrical non-cyclic alkynes.

graphic file with name Beilstein_J_Org_Chem-14-1317-i001.jpg
entry R1 R2 R3 conditions yield [%] ref.
1 Ph H H acetone, 170 °C, 25 h 75 [1–2]
2 Ph Me Ph 180 °C, 5 h 96–97 [1–2]
3 Ph H Ph 160 °C, 4.5 h 93 [2]
4 Ph Ph Ph 190 °C, 9 h 98 [2]
5 Ph H COOMe toluene, 90 °C, 4 h
xylene, reflux
p-xylene, reflux, overnight
p-xylene, reflux, overnight
p-xylene, reflux, 4 h		 92
92
98
93
93		 [1–2]
[20]
[26]
[29]
[31]
6 Ph Me COOMe xylene, 120 °C, 1 h 99 [1–2]
7 Bn H COOMe xylene, 120 °C, 5 h 93–98 [1–2]
8 Ph Cl COOMe ethyleneglycol, 120 °C, 1 h
xylene, reflux		 74
60–80		 [5]
[6]
9 Ph Br COOMe ethyleneglycol, 120 °C, 1 h
xylene, reflux		 70
60–80		 [5]
[6]
10 Me Cl COOMe ethyleneglycol, 120 °C, 1.5 h 12 [5]
11 Me Br COOMe ethyleneglycol, 120 °C, 1.5 h 82 [5]
12 Ph NO2 COOMe xylene, reflux 60–80 [6]
13 4-Br-Ph H COOMe xylene, reflux
p-xylene, reflux, 6 h		 60–80
92		 [6]
[35]
14 4-Br-Ph Br COOMe xylene, reflux 60–80 [6]
15 4-Br-Ph Cl COOMe xylene, reflux 60–80 [6]
16 4-Cl-Ph H COOMe xylene, reflux
p-xylene, reflux, overnight		 60–80
98		 [6]
[26]
17 4-Cl-Ph Br COOMe xylene, reflux 60–80 [6]
18 4-Cl-Ph Cl COOMe xylene, reflux 60–80 [6]
19 4-MeO-Ph H COOMe xylene, reflux
xylene, reflux, overnight
p-xylene, reflux, 4 h		 60–80
91
91		 [6]
[29]
[31]
20 4-MeO-Ph Br COOMe xylene, reflux 60–80 [6]
21 4-MeO-Ph Cl COOMe xylene, reflux 60–80 [6]
22 4-Br-3-Cl-Ph H COOMe xylene, reflux 89 [7]
23 4-Br-3-Cl-Ph Br COOMe xylene, reflux 71 [7]
24 4-Br-3-Cl-Ph Cl COOMe xylene, reflux 61 [7]
25 4-NO2-Ph H COOMe toluene, 110 °C, 1.75 h
p-xylene, reflux, overnight		 99
98		 [8]
[26]
26 4-NO2-Ph Ph COOMe toluene, 100–105 °C, 16 h 96 [8]
27 2,4-di-NO2-Ph Ph COOMe toluene, 100–105 °C, 4 h 97 [8]
28 Ph MeS COOMe toluene, 100 °C, 2 h 96 [8]
29 4-Me2N-Ph MeS COOMe mesitylene, 130–135 °C, 0.5 h 92 [8]
30 Ph PhS COOMe xylene, 120–125 °C, 5.75 h 91 [8]
31 Ph PhS=O COOMe mesitylene, 135–140 °C, 26 h 63 [8]
32 Ph MeC=O COOMe xylene, 160 °C, 18 h 62 [8]
33 4-MeO-Ph MeC=O COOMe mesitylene, 160–165 °C, 22 h 95 [8]
34 4-MeO-Ph CN COOMe xylene, 160 °C, 24 h 79 [8]
35 Me2N MeS COOMe xylene, 160 °C, 18 h
benzene, 80 °C, 16 h		 31
19		 [9]
36 Me2N MeS Ph xylene, 155–160 °C, 93 h 71 [9]
37 Me2N PhS COOMe xylene, 155–160 °C, 19 h
benzene, 80 °C, 23 h		 30
0		 [9]
38 Me2N H COOMe xylene, 155–160 °C, 3 h
benzene, 80 °C, 19 h		 9
2		 [9]
39 Me2N CN COOMe xylene, 155–160 °C, 3 h 0 [9]
40 O(CH2CH2)2N MeS COOMe benzene, 80 °C, 23 h 53 [9]
41 O(CH2CH2)2N PhS COOMe xylene, 155–160 °C, 22 h 70 [9]
42 (CH2)5N MeS COOMe xylene, 160 °C, 20 h 47 [9]
43 (CH2)5N PhS COOMe xylene, 150–160 °C, 24 h 27 [9]
44 graphic file with name Beilstein_J_Org_Chem-14-1317-i003.jpg COOMe benzene, reflux 71 [10]
45 graphic file with name Beilstein_J_Org_Chem-14-1317-i002.jpg COOMe benzene, reflux 77 [10]
46 4-MeCO-Ph H COOMe xylene, reflux 56 [11]
47 4-MeCO-Ph Me COOMe xylene, reflux 51 [11]
48 4-MeCO-Ph Ph COOMe xylene, reflux 38 [11]
49 4-(Me(Ph)NSO2)-Ph H COOMe xylene, reflux, 2 h 75 [12]
50 4-(Et(Ph)NSO2)-Ph H COOMe xylene, reflux, 2 h 75 [12]
51 4-(O(CH2CH2)2NSO2)-Ph H COOMe xylene, reflux, 2 h 78 [12]
52 4-((CH2)5NSO2)-Ph H COOMe xylene, reflux, 2 h 76 [12]
53 4-((CH2)4NSO2)-Ph H COOMe xylene, reflux, 2 h 75 [12]
54 4-(Et2NSO2)-Ph H COOMe xylene, reflux, 2 h 75 [12]
55 4-(O(CH2CH2)2NSO2)-Ph Br COOMe xylene, reflux, 2 h 66 [12]
56 4-((CH2)5NSO2)-Ph Br COOMe xylene, reflux, 2 h 70 [12]
57 CH2CH2CH2 Ph xylene, reflux, 48 h 45 [13]
58 CH2CH2CH2 COOMe xylene, reflux, 8 h 80 [13]
59 CH2CH2CH2 PhCO xylene, reflux, 8 h 92 [13]
60 graphic file with name Beilstein_J_Org_Chem-14-1317-i004.jpg Me COOMe xylene, 120 °C – [14]
61 graphic file with name Beilstein_J_Org_Chem-14-1317-i005.jpg Me COOMe xylene, 120 °C – [14]
62 graphic file with name Beilstein_J_Org_Chem-14-1317-i006.jpg Me COOMe xylene, 120 °C – [14]
63 graphic file with name Beilstein_J_Org_Chem-14-1317-i007.jpg Ph COOMe xylene, 120 °C – [14]
64 graphic file with name Beilstein_J_Org_Chem-14-1317-i008.jpg Ph COOMe xylene, 120 °C – [14]
65 graphic file with name Beilstein_J_Org_Chem-14-1317-i009.jpg Br COOMe xylene, 120 °C – [14]
66 graphic file with name Beilstein_J_Org_Chem-14-1317-i010.jpg Ph COOMe xylene, 120 °C – [14]
67 graphic file with name Beilstein_J_Org_Chem-14-1317-i011.jpg Ph COOMe xylene, 120 °C – [14]
67 graphic file with name Beilstein_J_Org_Chem-14-1317-i012.jpg Me COOMe xylene, 120 °C – [14]
68 CH2CH2CH2CH2 Ph p-xylene, reflux, 24 h, 91 [15]
69 Me H Ph 160 °C, 7 d 16 [15]
70 Me Ph COOMe p-xylene, reflux, overnight 77 [16]
71 graphic file with name Beilstein_J_Org_Chem-14-1317-i013.jpg H COOMe xylene, reflux 52 [17]
72 graphic file with name Beilstein_J_Org_Chem-14-1317-i014.jpg H COOMe xylene, reflux 60 [17]
73 graphic file with name Beilstein_J_Org_Chem-14-1317-i015.jpg H PhCO xylene, reflux 50 [17]
74 graphic file with name Beilstein_J_Org_Chem-14-1317-i016.jpg H PhCO xylene, reflux 53 [17]
75 Ph graphic file with name Beilstein_J_Org_Chem-14-1317-i017.jpg COOMe toluene, reflux 67 [18]
76 Ph graphic file with name Beilstein_J_Org_Chem-14-1317-i018.jpg COOt-Bu toluene, reflux 48 [18]
77 Me graphic file with name Beilstein_J_Org_Chem-14-1317-i019.jpg COOMe toluene, reflux 54 [18]
78 Ph H Bu3Sn xylene, reflux, 16 h 98 [19]
79 Me I COOMe toluene + DMSO, reflux, 6 h 84 [20]
80 CH2CH2CN I COOMe toluene, reflux, 6 h 95 [20]
81 Ph I COOMe toluene, reflux, 6 h 80 [20]
82 2-Me-Ph I COOMe toluene, reflux, 6 h 88 [20]
83 2-Et-Ph I COOMe toluene, reflux, 6 h 83 [20]
84 2-MeO-Ph I COOMe toluene, reflux, 6 h 83 [20]
85 3-MeO-Ph I COOMe toluene, reflux, 6 h 84 [20]
86 4-MeO-Ph I COOMe toluene, reflux, 6 h 90 [20]
87 2-Me-Ph Cl COOMe toluene, reflux, 6 h – [20]
88 2-Et-Ph Br COOMe toluene, reflux, 6 h 92 [20]
89 2,4-diMe-Ph I COOMe toluene, reflux 87 [21]
90 2,4-diMe-6-Br-Ph H COOMe toluene, reflux 82 [21]
91 2,4-diBr-6-Cl-Ph H COOMe toluene, reflux 90 [21]
92 2-Br-4,6-diMe-Ph I COOMe toluene, reflux 0 [21]
93 4-Br-2-Me-Ph H COOMe xylene, reflux, 8 h 83 [22]
94 4-Br-2-Me-Ph Cl COOMe xylene, reflux, 8 h 81 [22]
96 4-Br-2-Me-Ph Br COOMe xylene, reflux, 8 h 88 [22]
97 4-Br-2-Me-Ph I COOMe xylene, reflux, 8 h 79 [22]
98 4,6-Br2-2-Me-Ph H COOMe xylene, reflux, 8 h 92 [22]
99 4-Br-2-Me-Ph H COOEt xylene, reflux, 8 h 82 [22]
100 2,4-Br2-6-Me-Ph I COOMe(Et) xylene, reflux, 3 d 0 [22]
101 2-Cl-Ph I COOMe xylene, reflux, 8 h 78 [23]
102 2-Cl-4-Br-Ph I COOMe xylene, reflux, 8 h 87 [23]
103 2-Cl-4-Br-Ph H COOMe xylene, reflux, 8 h 91 [23]
104 4-Br-2-Et-Ph H COOMe toluene, reflux, 10 h 82 [24]
105 4-Br-2-Me-Ph I COOMe toluene, reflux, 10 h 90 [24]
106 2,5-diMe-Ph I COOMe toluene, reflux, 8 h 85 [25]
107 5-Cl-2-Me-Ph I COOMe toluene, reflux, 8 h 82 [25]
108 2,5-diMe-Ph Br COOMe toluene, reflux, 8 h 83 [25]
109 5-Cl-2-Me-Ph Br COOMe toluene, reflux, 8 h 87 [25]
110 2,4-diMe-Ph Br COOMe toluene, reflux, 8 h 81 [25]
111 2,4-diMe-Ph Cl COOMe toluene, reflux, 8 h 80 [25]
112 2,5-diMe-Ph H COOMe toluene, reflux, 8 h 80 [25]
113 5-Cl-2-Me-Ph H COOMe toluene, reflux, 8 h 80 [25]
114 2,4-diMe-Ph H COOMe toluene, reflux, 8 h 80 [25]
115 4-EtOOC-Ph H COOMe p-xylene, reflux, overnight 98 [26]
116 4-Me-Ph H COOMe p-xylene, reflux, overnight 98 [26]
117 4-EtO-Ph H COOMe p-xylene, reflux, overnight
xylene, 120 °C, 1 h		 98
94		 [26]
[27]
118 3-Cl-4-Me-Ph H COOMe xylene, 120 °C, 1 h 99 [27]
119 3-NO2-4-Me-Ph H COOMe xylene, 120 °C, 1 h 96 [27]
120 2,3-diMe-Ph H COOMe toluene, reflux, 10 h 89 [28]
121 2,3-diMe-Ph Cl COOMe toluene, reflux, 10 h 76 [28]
122 2,3-diMe-Ph Br COOMe toluene, reflux, 10 h 75 [28]
123 2,3-diMe-Ph I COOMe toluene, reflux, 10 h 77 [28]
124 2,3-diMe-Ph H COOCH2CF3 toluene, reflux, 12 h 83 [28]
125 Ph Ph COOMe toluene, reflux, 16 h 99 [30]
126 Ph 4-NO2-Ph COOMe toluene, reflux, 16 h 87 [30]
127 Ph 4-OCH3-Ph COOMe toluene, reflux, 16 h 82 [30]
128 Ph CF3 Ph o-dichlorobenzene, 24 h, 180 °C 53 [32]
129 Bn CF3 COOMe o-dichlorobenzene, 20 h, 120 °C (180 °C) 54a
(51)a 		[33]
130 Ph CH2F → CH2OH COOMe o-dichlorobenzene, 24 h, 100 °C 57 [33]
131 Ph graphic file with name Beilstein_J_Org_Chem-14-1317-i020.jpg COOMe o-dichlorobenzene, 5 min,
180 °C (μ-wave)		 92 [34]
132 4-MeO-Ph graphic file with name Beilstein_J_Org_Chem-14-1317-i021.jpg COOMe o-dichlorobenzene, 20 min,
180 °C (μ-wave)		 60 [34]
133 graphic file with name Beilstein_J_Org_Chem-14-1317-i022.jpg COOMe xylene, reflux, 3 h 70 [36]
134 graphic file with name Beilstein_J_Org_Chem-14-1317-i023.jpg COOMe toluene, 115 °C, overnight 81 [52]
135 2-MeO-Ph H, Br, Cl COOMe xylene, reflux n.d. [37]
136 2-NO2-Ph H, Br, Cl COOMe xylene, reflux n.d. [37]
137 3-NO2-Ph H, Br, Cl COOMe xylene, reflux n.d. [37]
138 2-Cl-Ph H, Br, Cl COOMe xylene, reflux n.d. [37]
139 3-Cl-Ph H, Br, Cl COOMe xylene, reflux n.d. [37]
140 Ph Ph PhCO toluene, heating, 92 h 69 [38]
141 Ph H PhCO PEG, 115 °C, 3 min, (μ-wave) 50 [39]
142 4-Cl-Ph H PhCO PEG, 115 °C, 3 min, (μ-wave) 51 [39]
143 4-Me-Ph H PhCO PEG, 115 °C, 3 min, (μ-wave) 54 [39]
144 Ph H 4-MeOPhCO PEG, 115 °C, 3 min, (μ-wave) 48 [39]
145 4-Cl-Ph H 4-MeOPhCO PEG, 115 °C, 3 min, (μ-wave) 48 [39]
146 4-Me-Ph H 4-MeOPhCO PEG, 115 °C, 3 min, (μ-wave) 49 [39]

aMixture of dimethyl 1-benzyl-5-trifluoromethyl-1H-pyrazole-3,4-dicarboxylate and dimethyl 1-benzyl-3-trifluoromethyl-1H-pyrazole-4,5-dicarboxylate in the ratio 96:4 (at 120 °C) or 63:37 (at 180 °C).