Notes
Organometallics, Vol. 24, No. 8, 2005 1995
pearance of compound 1. The solvent was removed under
reduced pressure, and the crude product was recrystallized
in cyclohexane at 40 °C (the compound is sensitive to temper-
ature), affording a white crystalline solid: mp 279-281 °C;
yield 1.05 g (2.18 mmol, 91%). 1H NMR (CDCl3): δ 1.17 (s,
6 and adducts 7-11 are included in the Supporting Informa-
tion.
Addition of 9-Triptycyldimethyltin Hydride (3) to
Substituted Alkynes Catalyzed by Bis(triphenylphos-
phine)palladium(II) Chloride. Typical Procedure. To a
solution of propargyl alcohol (0.047 g, 0.80 mmol) and bis-
(triphenylphosphine)palladium(II) chloride (0.010 g, 0.018
mmol) in dry THF (3 mL) under argon was added hydride 3
(0.34 g, 0.80 mmol), and the mixture was stirred at room
temperature for 2 h. Then, the solvent was distilled off under
reduced pressure. The 119Sn NMR spectrum of the crude
product showed a mixture of two compounds: (E)-â-3-tripty-
cyldimethylstannyl-2-propen-1-ol (14; 67%) and R-2-tripty-
cyldimethylstannyl-2-propen-1-ol (15; 33%). Column chroma-
tography (silica gel 60) of the mixture afforded 14 (yield 0.19
g (0.41 mmol, 52%): mp 70-72 °C) and 15 (yield 0.10 g (0.22
mmol, 28%); mp 174-176 °C) in the fractions eluted with 96:4
and 93:7 hexane-diethyl ether, respectively. NMR spectra,
physical characteristics, and other analytical data of adducts
12-15 are included in the Supporting Information.
Stille Coupling Reaction: Synthesis of Methyl 2-Phe-
nylpropenoate (16). To a mixture of bromobenzene (0.12 g,
0.74 mmol), PdCl2(PPh3)2 (0.011 g, 2%), and some crystals of
2,6-di-tert-butyl-4-methylphenol under argon was added a
solution of 8 (0.39 g, 0.81 mmol) in dry toluene (2 mL) at room
temperature, and this mixture was stirred for 24 h under
reflux, with monitoring by TLC. Column chromatography on
silica gel 60 of the crude product gave compound 16 (0.079 g,
0.48 mmol, 65%)7,8 in the fraction eluted with 98:2 hexane-
diethyl ether.
6H, 2J(Sn,H) ) 53.8 Hz); 5.31 (s, 1H); 6.83-7.46 (m, 12H). 13
C
NMR (CDCl3): δ 1.08 (1J(Sn,C) ) 357.2 Hz); 58.17 (1J(Sn,C)
) 358.6 Hz); 54.46; 123.48; 124.23; 124.97; 125.43; 146.24;
147.13. 119Sn NMR (CDCl3): δ 84.9.
Synthesis of 9-Triptycyldimethyltin Hydride (3). To a
suspension of LiAlH4 (0.20 g, 4.97 mmol) in dry diethyl ether
(10 mL) under an atmosphere of argon at room temperature
was added dropwise a solution of 9-triptycyldimethyltin bro-
mide (2; 2.00 g, 4.14 mmol) in THF (60 mL). The mixture was
heated under reflux for 3 h. THF was evaporated and replaced
by diethyl ether, and then a saturated solution of NH4Cl was
added. The organic layer was separated, and the aqueous layer
was extracted three times with diethyl ether. The combined
organic extracts were dried over anhydrous MgSO4. Removal
of the solvent under reduced pressure gave 3: mp 218-220
°C; yield 1.45 g (3.59 mmol, 87%). 1H NMR (CDCl3): δ 0.57 (s,
6H, 2J(Sn,H) ) 53.0 Hz); 5.27 (s, 1H); 5.80 (m, 1H, 1J(119Sn,1H)
) 1804.0 Hz); 6.73-7.47 (m, 12H). 13C NMR (CDCl3): δ -9.96
(1J(Sn,C) ) 357.2 Hz); 67.46; 55.13; 123.98; 124.87; 125.02;
125.26; 147.91; 148.52. 119Sn NMR (CDCl3): δ -128.5.
Synthesis of Methyl (2R,3S)- and (2S,3R)-2,3-diphenyl-
3-triptycyldimethylstannylpropanoate (5). To a solution
of hydride 3 (0.38 g, 0.94 mmol) in dry toluene (1 mL) was
added a solution of methyl (E)-2,3-diphenylpropenoate (4; 0.22
g, 0.94 mmol) in toluene (1 mL) and a catalytic amount of
AIBN. The mixture was stirred for 24 h at 90 °C under an
argon atmosphere. The reaction was monitored by taking
samples at intervals and observing the disappearance of the
Sn-H absorption by IR. Then the solvent was removed under
reduced pressure and the crude product was purified by
column chromatography (silica gel 60). Compound 5 was
isolated in the fraction eluted with hexane-diethyl ether (98:
Iododestannylation Reaction: Synthesis of (Z)-1-Iodo-
1,2-diphenylethene (17). To a solution of 10 (0.24 g, 0.41
mmol) in dry CH2Cl2 (4.5 mL) under argon was added iodine
(0.12 g, 0.45 mmol). The mixture was stirred at room temper-
ature for 30 min, with monitoring of the reaction by TLC.
Column chromatography on silica gel 60 of the crude product
gave iodovinyl compound 17 in the fraction eluted with
hexane: yield 0.12 g (quantitative); mp 136-138 °C. 1H NMR
(CDCl3): δ 7.27-7.82 (m). 13C NMR (CDCl3): δ 102.02; 126.04;
126.17; 126.68; 126.96; 127.41; 127.69; 134.98; 138.24; 138.77.
1
2): mp 221-223 °C; yield 0.47 g (0.73 mmol, 78%). H NMR
(CDCl3): δ 0.52 (s, 3H, 2J(Sn,H) ) 49.6 Hz); 0.58 (s, 3H,
3
2J(Sn,H) ) 49.6 Hz); 3.57 (s, 3H); 3.87 (d, 1H, J(H,H) ) 9.3,
3
3
2J(Sn,H) ) 59.9 Hz); 4.50 (d, 1H, J(H,H) ) 9.3, J(Sn,H) )
59.9 Hz); 5.18 (s, 1H); 6.61-7.41 (m, 22H). 13C NMR (CDCl3):
δ -6.13 (1J(Sn,C) ) 329.7 Hz); -4.23 (1J(Sn,C) ) 307.5 Hz);
39.91 (1J(Sn,C) ) 331.7 Hz); 52.49; 55.19 (2J(Sn,C) ) 16.0 Hz);
55.57; 57.69 (1J(Sn,C) ) 377.7 Hz); 123.87; 124.83; 125.09;
127.23; 128.38; 128.45; 128.70; 129.12 (3J(Sn,C) ) 23.9 Hz);
139.07 (3J(Sn,C) ) 42.6 Hz); 142.94 (2J(Sn,C) ) 28.5 Hz);
147.72; 175.13 (3J(Sn,CdO) ) 8.2 Hz).
Acknowledgment. This work was supported by the
CONICET (Capital Federal, Argentina), CIC (Buenos
Aires Province, Argentina), and Universidad Nacional
del Sur (Bah´ıa Blanca, Argentina). We acknowledge a
research grant from Fundacio´n Antorchas (Argentina).
The help of Prof. Jose´ Luis Mascaren˜as, University of
Santiago de Compostela (Spain), in connection with the
elemental analyses is acknowledged. A travel grant to
J.C.P. from the Alexander von Humboldt Foundation
and fellowships from the CONICET and DAAD (Ger-
many) to V.I.D. and from the CIC to D.C.G. are also
gratefully acknowledged.
Addition of 9-Triptycyldimethyltin Hydride (3) to
Substituted Alkynes under Radical Conditions. Typical
Procedure. A mixture of phenylethyne (0.076 g, 0.74 mmol),
hydride 3 (0.30 g, 0.74 mmol), and AIBN as a catalyst was
heated under argon at 60 °C for 1 h (this optimal time of
reaction and temperature was indicated by earlier experi-
ments, in which the reaction was monitored by taking samples
at intervals and observing the disappearance of the Sn-H
absorption by IR). The 1H, 13C, and 119Sn NMR spectra of the
crude product showed that it consisted of isomer (Z)-6 only.
Column chromatography (silica gel 60) of this product afforded
compound 6 (0.26 g, 0.52 mmol, 70%) in the fraction eluted
with hexane-diethyl ether (99:1): mp 153-155 °C. NMR
spectra, physical characteristics, and other analytical data of
Supporting Information Available: Characterization
data for the products including full 1H (Table 3) and 13C NMR
spectra (Table 4), as well as mass spectra and elemental
analyses of the isolated pure compounds. This material is
OM049104Z