170
H. S. Wilkinson et al. / Tetrahedron Letters 42 (2001) 167–170
with diglyme as solvent, 28–33% of 1 was converted to 4
B. K.; Saha, C. R. J. Catal. 1998, 173, 268. (e) Yu, Z.;
in 30 min.
Liao, S.; Xu, Y.; Yang, B.; Yu, D. J. Mol. Catal. A:
Chem. 1997, 120, 247.
10. The reduction of Fe(III) to Fe(II) can be visually ob-
served by the change in color from green to deep blue
upon addition of NaBH4. This color change occurred
prior to reduction of 1.
11. (a) The corresponding conversion without 2-bromo-
ethanol was 15% after 2 h with 2.0 mol% PcFe(II) and
1.8 equiv. of NaBH4. (b) The conversion of 4 to 6
occurred without racemization of the benzylic carbon
atom (determined by HPLC analysis). (c) The use of HCl
and 2-chloroethanol as additives had no observable effect
on the reaction rate or product distribution. Using 40
mol% HCl, 51% of 4 remained after 1 h, and 48% of 4
remained after 7 h.
12. A typical procedure is as follows: 4-(Aminophenyl)-
acetonitrile from 4-(nitrophenyl)acetonitrile. To a solu-
tion of 4-nitrophenylacetonitrile (162 mg, 1.0 mmol) in
diglyme (1 mL) was added Fe(II)-phthalocyanine (12 mg,
0.02 mmol, 0.02 equiv.), followed by addition of 2-bro-
moethanol (124 mL, 1.0 mmol, 1 equiv.) at 22°C. The
mixture was stirred at room temperature for 3 min,
followed by addition of sodium borohydride (0.5 M, 4
mL, 2 equiv.). The reaction mixture was stirred at room
temperature until the starting material was consumed
(monitored by HPLC). Ethyl acetate (30 mL) and water
(40 mL) were added and the reaction mixture was poured
into a separatory funnel and the aqueous layer was
discarded. The organic layer was washed with water
(2×20 mL) and concentrated in vacuo to yield the
product as a blue oil. Purification by flash chromatogra-
phy on silica gel (eluent: EtOAc:hex 1:4) yielded the
3. For rhodium-catalyzed reductions, see: (a) Nomura, K.;
Ishino, M.; Hazama, M. Bull. Chem. Soc. Jpn. 1991, 64,
2624. (b) Nomura, K.; Ishino, M.; Hazama, M. J. Mol.
Catal. 1991, 66, L11–L13. (c) Nomura, K.; Ishino, M.;
Hazama, M. J. Mol. Catal. 1991, 65, L5–L7. (d)
Nomura, K.; Ishino, M.; Hazama, M. J. Mol. Catal.
1993, 78, 273. For ruthenium-catalyzed reductions, see:
(a) Nomura, K. Chem. Lett. 1991, 1679. (b) Nomura, K.
J. Mol. Catal. 1992, 73, L1–L4. (c) Nomura, K.; Ishino,
M.; Hazama, M. J. Mol. Catal. 1993, 78, 273. For other
types of conditions, see: (a) Moody, C. J.; Pitts, M. R.
Synlett 1998, 1028; (b) Fischer, B.; Sheihet, L. J. Org.
Chem. 1998, 63, 393.
4. Yanada, K.; Yanada, R.; Meguri, H. Tetrahedron Lett.
1992, 33, 1463.
5. (a) Suzuki, H.; Manabe, H.; Inouye, M. Chem. Lett.
1985, 1671. (b) Yanada, K.; Yanada, R.; Meguri, H.
Tetrahedron Lett. 1992, 33, 1463. (c) Vizi-Orosz, A.;
Marko, L. Transition Met. Chem. 1991, 16(2), 215. (d)
Cho, J. G.; Potter, W. T.; Sublette, K. L. Appl. Biochem.
Biotechnol. 1994, 2273.
6. Another method for the conversion of 1 to 2 is described
in: Wilkinson, H. S.; Tanoury, G. J.; Senanayake, C. H.;
Wald, S. A. Org. Proc. Res. Dev. 2000, 4, 567.
7. (a) Aoyama, Y.; Fujisawa, T.; Watanabe, T.; Toi, H.;
Ogoshi, H. J. Am. Chem. Soc. 1983, 86, 943. (b) Barley,
M.; Takeuchi, K.; Meyer, T. J. Am. Chem. Soc. 1983, 86,
5876. (c) Aoyama, Y.; Midorikawa, K.; Toi, H.; Ogoshi,
H. Chem. Lett. 1987, 1651.
1
desired product (130 mg, 98% yield) as a yellow oil. H
8. (a) Cho, J. G.; Potter, W. T.; Sublette, K. L. Appl.
Biochem. Biotechnol. 1994, 2273. (b) Sakai, L.; Mitarai,
S.; Ohkubo, K. Chem. Lett. 1991, 195.
NMR (300 MHz, CDCl3): l 3.75 (s, 2H), 4.83 (s, 2H),
6.73 (d, 2H), 7.07 (d, 2H). 13C NMR (75 MHz, CDCl3):
l 22.81, 116.80, 120.46, 120.80, 129.90, 148.71.
9. Ru(TPP) and Ni(TPP) catalysts were also used. With
both catalysts, under an atmosphere of Ar or air, and
13. No products corresponding to dehalogenation of the
haloarenes were observed by HPLC and NMR analysis.
.