Checked by Scott E. Denmark and Tetsuya Kobayashi.
1. Procedure
2. Notes
1.
Carbon tetrabromide (99%) was purchased from the Aldrich Chemical Company Inc. and was used without further purification.
2.
Dichloromethane (unstabilized HPLC grade) was purchased from Fisher Scientific and was dried by percolation through two columns packed with neutral alumina under a positive pressure of argon.
3.
Triphenylphosphine (99%) was purchased from the Aldrich Chemical Company Inc. and was used without further purification.
4.
3-Phenylpropionaldehyde (>90%) was purchased from Fluka and was purified by distillation.
5.
The product displayed the following properties: R
f 0.73 (
10:1 hexane-ether); IR (CHCl
3): cm
−1 3087, 3066, 3030, 3015, 2928, 2861, 1604, 1496, 1454, 1083, 1030, 907;
1H NMR (500 MHz, CDCl
3): δ 2.42 (q,
J = 7.7 Hz, 2 H), 2.74 (t,
J = 7.7 Hz, 2 H), 6.42 (t,
J = 7.7 Hz, 2 H), 7.19 (br d,
J = 7.6 Hz, 2 H), 7.22 (br t,
J = 7.6 Hz, 1 H), 7.31 (br t,
J = 7.6 Hz, 2 H);
13C NMR (125.7 MHz, CDCl
3): δ 33.8, 34.6, 89.5, 126.3, 128.4 (2C), 128.5 (2C), 137.6, 140.6. LRMS EI (relative intensity)
m/
z: 292 (M
++2, 1.0), 290 (M
+, 1.9), 288 (M
+-2, 1.2), 227 (0.9), 225 (1.0), 221 (49), 209 (52), 129 (23), 128 (20), 92 (43), 91 (100), 77 (13). Anal. Calcd for C
10H
10 Br
2: C; 41.42, H; 3.48. Found: C; 41.33, H; 3.40. The spectroscopic data were identical with literature values for material previously prepared by this procedure.
2
6.
Dry
HPLC grade tetrahydrofuran was purchased from Fisher and was dried by percolation through two columns packed with neutral alumina under a positive pressure of argon.
7.
A
hexane solution of
n-butyllithium was purchased from the Aldrich Chemical Company Inc. and was titrated prior to use.
8.
Paraformaldehyde was purchased from Fisher and was used without further purification.
9.
5-Phenylpent-2-yn-1-ol exhibits the following properties: R
f 0.25 (3:1
hexane-ethyl acetate); IR (CHCl
3): cm
−13610 (OH), 3088, 3066, 3029, 3013, 2932, 2874, 2360, 2223, 1604, 1496, 1455, 1430, 1385, 1342, 1233, 1133, 1078, 1006, 968;
1H NMR (500 MHz, CDCl
3): δ 1.60 (t,
J = 6.0 Hz, 1 H), 2.52 (tt,
J = 7.5, 2.1 Hz, 2 H), 2.84 (t,
J = 7.5 Hz, 2 H), 4.23 (dt,
J = 6.0, 2.1 Hz, 2 H), 7.18-7.26 (m, 3 H), 7.31 (br t,
J = 7.3 Hz, 2 H);
13C NMR (125.7 MHz, CDCl
3): δ 20.9, 34.9, 51.3, 79.0, 85.7, 126.3, 128.38 (2C), 128.40 (2C), 140.5; LRMS EI (relative intensity)
m/
z: 160 (M
+, 1.2), 159 (5), 142 (32), 129 (15), 92 (10), 91 (100), 65 (14). Anal. Calcd for C
11H
12O: C, 82.46; H, 7.55. Found: C, 82.27; H, 7.68.
10.
Pyridine (99.9%) was purchased from Fisher and was purified by distillation over CaH
2.
11.
Acetic anhydride (99.7%) was purchased from Fisher and was purified by distillation.
12.
Acetic acid 5-phenylpent-2-ynyl ester has the following properties: R
f 0.5 (3:1
hexane-ethyl acetate); IR (CHCl
3): cm
−1 3066, 3028, 2948, 2865, 2237 (alkyne), 1737 (CO), 1604, 1496, 1454, 1438, 1380, 1360, 1224, 1210, 1147, 1078, 1026, 967;
1H NMR
pdf (500 MHz, CDCl
3): δ 2.09 (s, 3 H), 2.52 (tt,
J = 7.7, 2.1 Hz, 2 H), 2.84 (t,
J = 7.7 Hz, 2 H), 4.65 (t,
J = 2.1 Hz, 2 H), 7.18-7.24 (m, 3 H), 7.30 (br t,
J = 7.1 Hz, 2 H);
13C NMR (125.7 MHz, CDCl
3): δ 20.8, 20.9, 34.8, 52.7, 74.7, 86.8, 126.4, 128.4 (4C), 140.4, 170.4; LRMS EI (relative intensity)
m/
z: 202 (M
+, 0.14), 201 (0.85), 160 (14), 142 (33), 141 (18), 92 (10), 91 (100), 65 (13). Anal. Calcd for C
13H
14O
2: C, 77.20; H, 6.98. Found: C, 77.37; H, 7.20.
13.
Toluene (99.9%) is purchased from Fisher and dried by distillation under argon from
sodium benzophenone ketyl.
14.
Second-generation
ruthenium-carbene complex, (tricyclohexylphosphine-[1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene]ruthenium (IV) dichloride),4e was purchased from Strem Chemicals.
15.
The
ethylene gas bag was purchased from the Aldrich Chemical Company, Inc., catalog number Z 18,674-0.
16.
Ethylene was purchased from Matheson (>99.5%) and was purified by bubbling it sequentially through an aqueous solution of CuCl (
2 g of CuCl in 200 mL of saturated aqueous NH4Cl), concentrated H
2SO
4, and then a KOH tube as shown in Figure 1. The reaction apparatus for the synthesis of the 1,3-diene is shown in Figure 2.
17.
The checkers found that this purification of
ethylene was not necessary. Without the purification, the checkers obtained the product quantitatively after purification by chromatography and in 97% yield after distillation.
Ethyl vinyl ether is added to quench the reaction.
5
Figure 1. Purification of Ethylene Gas
Figure 2. Reaction Apparatus for the Synthesis of 1,3-Diene
18.
Ethyl vinyl ether was purchased from the Aldrich Chemical Company Inc. and was used without purification.
19.
2-Methylene-3-phenethylbut-3-enyl acetate has the following properties: R
f 0.55 (3:1
hexane-ethyl acetate); IR (CHCl
3): cm
−13690, 3087, 3065, 3020, 2945, 2865, 2360, 2342, 1736, 1635, 1601, 1496, 1455, 1370, 1222, 1046, 1030, 905;
1H NMR
pdf (500 MHz, CDCl
3): δ 2.11 (s, 3 H), 2.58 (br t,
J = 8.1 Hz, 2 H), 2.80 (br t,
J = 8.1 Hz, 2 H), 4.80 (s, 2 H), 5.03 (br s, 1 H), 5.10 (s, 1 H), 5.31 (br s, 1 H), 5.37 (s, 1 H), 7.16-7.23 (m, 3 H), 7.29 (br t,
J = 7.3 Hz, 2 H);
13C NMR (125.7 MHz, CDCl
3): δ 21.0, 34.7, 35.9, 65.2, 113.1, 114.8, 125.9, 128.34 (2C), 128.38 (2C), 141.4, 141.9, 144.2, 170.8; LRMS EI (relative intensity)
m/
z: 230 (M
+, 0.04), 170 (30), 155 (28), 142 (37), 141 (17), 130 (21), 129 (20), 128 (14), 104 (10), 92 (18), 91 (100), 65 (15). Anal. Calcd for C
13H
18O
2: C, 78.23; H, 7.88. Found: C, 78.26; H, 7.91.
20.
The checkers found that although the chromatographed product was a light yellow oil, it was analytically pure. Kugelrohr distillation was required to obtain a colorless oil.
The procedures in this article are intended for use only by persons with prior training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011 www.nap.edu). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices.
These procedures must be conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.
3. Discussion
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
3-Phenylpropionaldehyde:
Benzenepropanal; (104-53-0)
(4,4-Dibromobut-3-enyl)benene:
Benzene, (4,4-dibromo-3-butenyl)-; (119405-97-9)
5-Phenylpent-2-yn-1-ol:
2-Pentyn-1-ol, 5-phenyl-; (16900-77-9)
Acetic acid 5-phenylpent-2-ynyl ester:
2-Pentyn-1-ol, 5-phenyl-, acetate; (445234-71-9)
Acetic acid 2-methylene-3-phenethylbut-3-enyl ester:
Benzenepentanol,
βγ-bis(methylene)-, acetate; (445234-76-4)
Carbon tetrabromide:
Methane, tetrabromo-; (558-13-4)
Triphenylphosphine:
Phosphine, triphenyl-; (603-35-0)
Butyllithium:
Lithium, butyl-; (109-72-8)
Paraformaldehyde; (30525-89-4)
Acetic anhydride:
Acetic acid, anhydride; (108-24-7)
Pyridine; (108-24-7)
Tricyclohexylphosphine[1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene]ruthenium(IV)dichloride:
Ruthenium, [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(phenylmethylene)(tricyclohexylphosphine)-,
(SP-5-41)-; (246047-72-3)
Ethyl vinyl ether;
Ethene, ethoxy-; (109-92-2)
Ethylene:
Ethene; (74-85-1)
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