Carbenoid Etherifications Catalyzed by “Green” Silver Nanoparticles
Letters in Organic Chemistry, 2012, Vol. 9, No. 1
5
6.93 (s, 1H). 13C-NMR (125 MHz, CDCl3) ꢀ: 22.2, 22.3,
56.1, 56.3, 56.4, 65.6, 69.1, 97.4, 113.2, 118.36, 142.9,
148.9, 151.5. MS [EI+] m/z (%) 240 [M]+ (20) 225 [M -
CH3]+ (100) HRMS (EI+): for C13H20O4 calcd. 240.1362,
found 240.1367.
[M]+ (10), 135 [M-C6H5]+ (100). HRMS (EI+): for C14H14O
calcd. 212.1201, found 212.1208.
2-Butoxymethyl-1,3-dichlorobenzene (entry 5, Table 3)
Colorless oil. IR (KBr, cm-1) 2958, 1603, 1345. 1H-NMR
(500 MHz, CDCl3) ꢀ: 0.97 (t, 2H), 1.29-1.65 (m, 4H), 3.59
(t, 2H), 4.95 (s, 2H), 7.11-7.67 (m, 3H). 13C-NMR (125
MHz, CDCl3) ꢀ: 13.9, 19.1, 31.8, 70.9, 76.7, 126.9, 129.8,
133.6, 135.6, 138.9. MS [EI+] m/z (%) 232 [M]+ (50) 189
[M- C3H7] (100). HRMS (EI+): for C11H14Cl2O calcd.
232.0422, found 232.0426.
1,3-Dichloro-2-isopropoxymethylbenzene (entry 5, Table 1,
and entry 4, Table 3)
Colorless oil. IR (KBr, cm-1) 2959, 1603, 1345. 1H-NMR
(500 MHz, CDCl3) ꢀ ppm: 1.44 (d, 6H), 3.84-3.97 (m, 1H),
5.73 (s, 2H), 7.43-7.62 (m, 3H). 13C-NMR (125 MHz,
CDCl3) ꢀ ppm: 22.5, 69.2, 76.9, 127.3, 127.4, 129.1, 143.2.
MS [EI+] m/z (%) 218 [M]+ (100). HRMS (EI+): for
C10H12Cl2O calcd. 218.0265, found 218.0268.
1,3-Dichloro-2-ethoxymethyl-benzene (entry 6, Table 3)
Colorless oil. IR (KBr, cm-1) 2958, 1603, 1345. 1H-NMR
(500 MHz, CDCl3) ꢀ: 1.16 (t, 2H), 4.09 (q, 2H), 4.98 (s, 2H),
7.11-7.67 (m, 3H). 13C-NMR (125 MHz, CDCl3) ꢀ: 14.1,
56.4, 69.9, 126.9, 129.8, 133.6, 135.6, 138.9. MS [EI+] m/z
(%) 204 [M]+ (50) 189 [M- CH3]+ (100). HRMS (EI+): for
C11H14Cl2O calcd. 204.0109, found 204.0110.
Preparation of Iron-Copper Nanoparticles
.
A solution of FeSO4 7H2O (2.30 g; 7.5 mmol) in H2O
.
(750 mL) was added to solution of CuSO4 5H2O (0.69 g; 2.5
mmol) in H2O (250 mL). The resulting mixture was stirred
with mechanical stirring (300 rpm) at room temperature. A
solution of 0.5 M NaOH was added dropwise to pH=7.
When pH was adjusted, a solution of NaBH4 (0.757 g; 20
mmol) in H2O (100 mL) was added, a vigorous evolution of
hydrogen occurred, and the resulting dark mixture was
stirred at room temperature for 15 min. The mixture was
filtered, and the precipitate was washed successively with
water and acetone. The nanoparticles were dried in vacuo at
room temperature for 24 h.
1,2,4-Trimethoxy-5-methoxymethyl-benzene (entry 8, Table
3)
Colorless oil. IR (KBr, cm-1) 2957, 1603, 1347. 1H-NMR
(500 MHz, CDCl3) ꢀ: 3.81 (s, 3H), 3.84 (s, 3H), 3.85 (m,
6H), 4.55 (s, 2H), 6.56 (s, 1H), 6.93 (s, 1H). 13C-NMR (125
MHz, CDCl3) ꢀ: 56.1, 56.2, 56.3, 56.4, 65.6, 66.9, 97.4,
113.2, 118.36, 142.9, 148.9, 151.5. MS [EI+] m/z (%) 212
[M]+ (40) 181 [M- CH3O]+ (100) HRMS (EI+): for
C11H16O4 calcd. 212.1049, found 212.1046.
1-Ethoxymethyl-2,4,5-trimethoxy-benzene (entry 9, Table
3)
Carbenoid
Etherifications
using
Iron-Copper
Colorless oil. IR (KBr, cm-1) 2957, 1603, 1347. 1H-NMR
(500 MHz, CDCl3) ꢀ: 1.21- (t, 3H), 3.51 (q, 2H), 3.81 (s,
3H), 3.84 (s, 3H), 3.85 (s, 3H), 4.51 (s, 2H), 6.51 (s, 1H),
6.92 (s, 1H). 13C-NMR (125 MHz, CDCl3) ꢀ: 15.2, 56.1,
56.3, 56.4, 65.6, 66.9, 97.4, 113.2, 118.36, 142.9, 148.9,
151.5. MS [EI+] m/z (%) 226 [M]+ (50) 211 [M- CH3]+
(100) HRMS (EI+): for C12H18O4 calcd. 226.1205, found
226.1206.
Nanoparticles
Typical Procedure
Sodium (0.080 g, 3.5mmol) was added to the
corresponding anhydrous alcohol (10 mL), and the resulting
mixture was stirred at 50ºC under a nitrogen atmosphere for
1 h to dissolve the sodium completely. The solution was
cooled to room temperature and a solution of the appropriate
tosylhydrazone (3.2 mmol) in alcohol( 10 mL) was added.
The reaction mixture was stirred at 50ºC for 2 h and iron-
copper nanoparticles (0.01g) were added. The resulting
reaction mixture was stirred at reflux temperature for 12 h.
The mixture was cooled to room temperature and the solvent
was removed in vacuo. Purification by column
chromatography (SiO2, hexane/AcOEt 9:1) afforded the
corresponding ethers and azines according to table 3.
ACKNOWLEDGEMENTS
Financial support from SIEA-UAEMEX is gratefully
acknowledged. The authors would like to thank Signa, S.A.
de C.V. for some graciously donated solvents and reagents,
and M. C. Nieves Zavala for the technical support.
Methoxydiphenylmethane (entry 2, Table 3)
REFERENCES
Colorless oil. IR (KBr, cm-1) 1598, 1355. H NMR (500
1
MHz, CDCl3) ꢀ 3.85 (s, 3H), 5.41 (s, 1H), 7.25 (m, 10H). 13
C
[1]
Doyle, M.P. ; McKervey, M. A. ; Ye, T. Modern catalytic methods
for organic synthesis with diazo compounds: from cyclopropanes to
ylides; Wiley: New York, 1998.
NMR (125 MHz, CDCl3) ꢀ 56.2, 80.4, 126.2, 127.1, 128.2,
142.4. MS [EI+] m/z (%) 198 [M]+ (6), 121 [M-C6H5]+
(100). HRMS (EI+): for C14H14O calcd. 198.1045, found
198.1048.
[2]
Fulton, J.R.; Aggarwal, V. K.; Vicente, J. The Use of
Tosylhydrazone Salts as a Safe Alternative for Handling Diazo
Compounds and Their Applications in Organic Synthesis. Eur. J.
Org. Chem. 2005, 1479-1492.
[3]
Aggarwal, V. K.; Alonso, E.; Bae, I.; Hynd, G.; Lydon, K. M.;
Palmer, M. J.; Patel, M.; Porcelloni, M.; Richardson, J.; Stenson, R.
A.; Studley, J. R.; Vasse, J. L.; Winn, C. L. A New Protocol for the
In Situ Generation of Aromatic, Heteroaromatic, and Unsaturated
Diazo Compounds and Its Application in Catalytic and Asymmetric
Epoxidation of Carbonyl Compounds. Extensive Studies To Map
Out Scope and Limitations, and Rationalization of Diastereo- and
Enantioselectivities. J. Am. Chem. Soc. 2003, 125, 10926-10940.
Ethoxydiphenylmethane (entry 3, Table 3)
Colorless oil. IR (KBr, cm-1) 1599, 1355. H NMR (500
MHz, CDCl3) ꢀ 1.25 (t, 3H), 4.04 (q, 2H), 5.45 (s, 1H), 7.25-
7.35 (m, 10H). 13C NMR (125 MHz, CDCl3) ꢀ 14.1, 63.2,
80.4, 126.2, 127.1, 128.2, 142.4. MS [EI+] m/z (%) 212
1