References
1a
Sonogashira K. In Comprehensive
Organic Synthesis
Vol. 3:
Trost B.
Flemming I.
Pattenden G.
Pergamon Press;
New
York:
1991.
p.521
1b
Sonogashira K. In Metal-catalyzed Cross-coupling Reactions
Diederich F.
Stang PJ.
Wiley-VCH;
Weinheim:
1998.
p.203
2 Besides secondary amines, primary amines
such as tert-butylamine, also gave the
propargylic amine product in this three component reaction, albeit
in lower yields (46%).
3a
Martinelli MJ.
Nayyar NK.
Moher ED.
Dhokte UP.
Pawlak JM.
Vaidyanathan R.
Org. Lett.
1999,
1:
447
3b The tosylation of propargylic
alcohols (n = 1) under these conditions gave the desired
products only in moderate yields (up to 25%) accompanied
with the corresponding propargylic chloride in up to 35% yield
and recovered starting material.
For recent cobalt(I)-catalyzed Diels-Alder
reactions see:
4a
Hilt G.
Lüers S.
Polborn K.
Isr.
J. Chem.
2001,
41:
317
4b
Hilt G.
Smolko KI.
Synthesis
2002,
686
4c
Hilt G.
Smolko KI.
Synlett
2002,
1081
5 Typical procedure: Preparation of 3-[2-(2-bromophenyl)-4,5-dimethyl-1,4-cyclohexadien-1-yl]propyl
4-methylbenzenesulfonate (Scheme
[4]
,
n = 3): To 5-(2-bromophenyl)-4-pentynyl-4-methylbenzenesulfonate
(321 mg, 0.82 mmol) in dry CH2Cl2 (2.0 mL)
were added CoBr2(dppe) (40 mg, 0.07 mmol, 9 mol%),
2,3-dimethyl-1,3-butadiene (145 mg, 1.77 mmol, 2.0 equiv), zinc
(300 mg, 4.69 mmol, 5.7 equiv) and ZnBr2 (100 mg, 0.45
mmol, 55 mol%) under nitrogen atmosphere. The reaction
mixture was stirred at room temperature overnight. The crude product was
purified by column chromatography (SiO2, pentane:diethyl
ether = 2:1) affording the desired product (381 mg, 0.80
mmol, 98%) as a colorless oil.
1H
NMR (300 MHz, C6D6): δ = 7.70-7.64
(m, 2 H), 7.39 (dd, J = 8.4,
1.1 Hz, 1 H), 7.00-6.85 (m, 2 H), 6.74-6.64 (m,
3 H), 4.77-3.63 (m, 2 H), 3.02-2.84 (m, 1 H),
2.56-2.34 (m, 3 H), 1.82 (s, 3 H), 1.80-1.35 (m,
10 H); 13C NMR (75 MHz, C6D6): δ = 143.9,
143.6, 134.6, 133.0, 131.8, 130.6, 130.4, 129.7, 128.4, 128.1, 127.8,
123.6, 123.0, 122.8, 70.1, 39.4, 36.6, 29.4, 27.2, 21.1, 18.2, 17.9;
MS m/z (%) = 474
(M+, 2), 208(15), 194(24), 179(12), 91(11),
74(100); HRMS calcd for C24H27BrO3S: m/z = 474.0864,
found: m/z = 474.0811.
6
Parham WE.
Bradsher CK.
Acc. Chem. Res.
1982,
15:
300
7a Typical
procedure: Preparation of 7-methoxy-2,3-dimethyl-1,4,9,10-tetrahydrophenanthrene
(Scheme
[5]
): To 2-[2-(2-bromo-4-methoxyphenyl)-4,5-dimethyl-1,4-cyclohexadien-1-yl]ethyl
4-methylbenzenesulfonate (134 mg, 0.27 mmol) in anhyd THF (5.0 mL)
at -90 °C was added tert-butyllithium
(0.4 mL, 1.7 M in THF, 0.56 mmol, 2.1 equiv) in one portion under
nitrogen atmosphere. The reaction mixture was allowed to warm up
to room temperature. After water addition (1.0 mL), the reaction mixture
was extracted with diethyl ether (4 × 50 mL) and the combined
organic phases were dried over MgSO4. The solvent was
removed and the crude product was purified by column chromatography
(SiO2, pentane) affording the desired product (54 mg,
0.23 mmol, 82%) as a colorless crystalline solid.
1H
NMR (300 MHz, CDCl3): δ = 7.13 (d, J = 8.0 Hz, 1 H), 6.75-6.65
(m, 2 H), 3.81 (s, 3 H), 2.94 (t, J = 7.1
Hz, 2 H), 2.84-2.70 (m, 4 H), 2.20 (t, J = 8.3
Hz, 2 H), 1.77 (s, 3 H), 1.72 (s, 3 H); 13C
NMR (75 MHz, CDCl3): δ = 157.9, 137.2, 128.8,
128.5, 123.9, 123.5, 122.7, 122.6, 113.6, 110.7, 55.2, 39.0, 33.3,
28.5, 28.1, 18.5, 18.1; MS m/z (%) = 240
(M+, 91), 238(75), 225(100), 210(26), 165(20);
HRMS calcd for C17H20O: m/z = 240.1514, found: m/z = 240.1522.
7b For a recent flexible
synthesis of phenanthrene derivatives see: Fürstner A.
Mamane V.
J. Org. Chem.
2002,
67:
6264 ; and references cited therein
8
Schlosser M. In Organometallics in Synthesis
Wiley;
Chichester:
1994.
p.129-133
9 Typical procedure: Preparation of 1,4,5,6,7,8-hexahydro-2,3-dimethyl-dibenzo[a,c]cyclooctene
(Scheme
[6]
, structure at
the bottom): To 4-[2-(2-bromophenyl)-4,5-dimethyl-1,4-cyclohexadien-1-yl]butyl
4-methylbenzenesulfonate (1.282 g, 2.62 mmol) in dry diethyl ether
(5.0 mL) at -100 °C tert-butyllithium
(3.74 mL, 1.4 M in THF, 5.24 mmol, 2.0 equiv) was added slowly,
such that the reaction temperature did not exceed -80 °C.
Then, the reaction mixture was allowed to warm up to room temperature.
After water (2.0 mL) was added, the reaction mixture was extracted
with diethyl ether (4 × 50 mL) and the combined organic
phases were dried over MgSO4. The solvent was removed
and the crude product was purified by column chromatography (SiO2, pentane)
affording the desired product (437 mg, 1.84 mmol, 70%)
as a colorless oil.
1H NMR (300 MHz,
C6D6): δ = 7.22-7.08
(m, 4 H), 3.16-3.00 (m, 1 H), 2.90-2.75 (m, 1
H), 2.70-2.40 (m, 4 H), 1.98-1.80 (m, 2 H), 1.77 -1.49
(m, 8 H), 1.44-1.11 (m, 2 H); 13C NMR
(75 MHz, C6D6): δ = 142.2
(Cq), 141.5(Cq), 132.2(Cq), 129.7
(CH), 128.5 (Cq), 127.4 (CH), 127.1 (CH), 125.8 (CH),
123.7 (Cq), 123.3 (Cq), 38.8 (CH2),
38.6 (CH2), 33.5 (CH2), 32.1 (CH2),
30.4 (CH2), 24.2 (CH2), 18.2 (CH3),
18.1 (CH3); MS m/z (%) = 238
(M+, 100), 223(18), 195(50), 181(57), 165(22);
HRMS calcd for C18H22: m/z = 238.1721, found: m/z = 238.1714.
Analytical
data for 1,4,6,7-tetrahydro-2,3-dimethyl-dibenzo[a,c]cycloheptene
(Scheme
[6]
, structure at
the top):
1H NMR (300 MHz, CDCl3): δ = 7.25-7.02
(m, 4 H), 2.96-2.87 (m, 2 H), 2.83-2.74 (m, 2
H), 2.48 (t, J = 7.1 Hz, 2 H), 2.10-1.98
(m, 2 H), 1.77 (t, J = 6.7 Hz,
2 H), 1.64 (s, 6 H); 13C NMR (75 MHz,
C6D6): δ = 142.2 (Cq),
140.3 (Cq), 132.4 (Cq), 128.6 (CH), 128.2
(Cq), 126.1 (CH), 125.9 (CH), 125.4 (CH), 123.8 (Cq),
123.2 (Cq), 39.3 (CH2), 36.9 (CH2),
33.6 (CH2), 32.3 (CH2), 29.8 (CH2),
18.3 (CH3), 18.1 (CH3); MS m/z (%) = 224
(M+, 100), 209(51), 195(24), 181(38), 165(22),
121(27); HRMS calcd for C17H20: m/z = 224.1565, found: m/z = 224.1572.
