PAPER
Highly Efficient Method for the Reductive Etherification of Carbonyl Compounds
185
13C NMR: d = 71.29, 72.24, 121.40, 127.70, 128.38, 129.28, 131.42,
137.23, 137.89.
Table 4 Synthesis of Various Ethers from 3-Phenylpropionalde-
hyde
1.2 equiv
CHO
4-Benzyloxymethyl-1-nitrobenzene (2k)
+
ROTMS
IR (neat): 2859, 1605, 1521, 1346, 1100, 739, 699, 661 cm–1.
Ph
1a
1.2 equiv 5 mol%
Et3SiH / FeCl3
1H NMR: d = 4.62 (s, 2 H), 4.64 (s, 2 H), 7.31–7.39 (m, 5 H), 7.52
(d, J = 8.8 Hz, 2 H), 8.20 (d, J = 8.8 Hz, 2 H).
13C NMR: d = 70.77, 72.85, 123.54, 127.68, 127.71, 127.89, 128.47,
137.45, 145.86, 147.28.
Ph
OR
CH3NO2 / 0 °C to r.t.
2
Entry
ROTMS
Time
(min)
Product Yield of 2
(%)a
Methyl 4-(Benzyloxymethyl)benzoate (2l)
IR (neat): 1721, 1436, 1281, 1109, 1019, 757 cm–1.
1
2
3
4
CH2=CHCH2OTMS
n-BuOTMS
10
2s
2t
81
89
70
33b
1H NMR: d = 3.89 (s, 3 H), 4.57 (s, 2 H), 4.59 (s, 2 H), 7.26–7.38
(m, 5 H), 7.42 (d, J = 8.1 Hz, 2 H), 8.02 (d, J = 8.1 Hz, 2 H).
13C NMR: d = 52.00, 71.37, 72.42, 127.13, 127.65, 128.33, 129.22,
129.58, 129.63, 137.76, 143.47, 166.74.
10
cyclo-C6H11OTMS
t-BuOTMS
15
2u
2v
30
4-(Benzyloxymethyl)phenyl acetate (2m)
a Isolated yield of purified product.
IR (neat): 2858, 1759, 1508, 1368, 1195, 1092, 910 cm–1.
b The lower yield was due to a complicated reaction mixture.
1H NMR: d = 2.30 (s, 3 H), 4.54 (s, 2 H), 4.56 (s, 2 H), 7.07 (d, J =
8.4 Hz, 2 H), 7.28–7.39 (m, 7 H).
13C NMR: d = 21.20, 71.44, 72.17, 121.45, 127.60, 127.70, 128.35,
and triethylsilane (116 mL, 0.727 mmol) successively at 0 °C under
an Ar atmosphere. After stirring for 10 min at r.t., the reaction mix-
ture was quenched with a phosphate buffer (pH 7, 20 mL). The or-
ganic materials were extracted with CH2Cl2, washed with brine, and
dried over Na2SO4. 1-Benzyloxy-3-phenylpropane (2a; 123.3 mg,
91%) was isolated by TLC on silica gel.
128.70, 136.85, 138.03, 149.97, 169.37.
1-Acetyl-4-(benzyloxymethyl)benzene (2n)
IR (neat): 2858, 1683, 1609, 1359, 1267, 1092, 698 cm–1.
1H NMR: d = 2.60 (s, 3 H), 4.59 (s, 2 H), 4.61 (s, 2 H), 7.25–7.37
(m, 5 H), 7.46 (d, J = 8.2 Hz, 2 H), 7.95 (d, J = 8.2 Hz, 2 H).
13C NMR: d = 26.70, 71.40, 72.51, 127.36, 127.70, 127.73, 128.40,
128.42, 136.36, 137.80, 143.75, 197.65.
1-Benzyloxy-2-phenylpropane (2b)
IR (neat): 3364, 1453, 1098, 698 cm–1.
1H NMR: d = 1.31 (d, J = 7.0 Hz, 3 H), 3.07 (dqd, J = 7.7, 7.0, 6.2
Hz, 1 H), 3.50 (dd, J = 7.7, 9.2 Hz, 1 H), 3.59 (dd, J = 9.2, 6.2 Hz,
1 H), 4.50 (s, 2 H), 7.18–7.36 (m, 10 H).
13C NMR: d = 18.46, 40.10, 72.96, 76.11, 126.24, 127.29, 127.36,
127.43, 128.25, 138.46, 144.32.
2-(Benzyloxymethyl)naphthalene (2o)
IR (neat): 3056, 1335, 1128, 818, 732 cm–1.
1H NMR: d = 4.59 (s, 2 H), 4.71 (s, 2 H), 7.27–7.51 (m, 8 H), 7.79–
7.85 (m, 4 H).
13C NMR: d = 72.10, 72.18, 125.72, 125.76, 126.00, 126.41, 127.59,
127.75, 127.78, 128.09, 128.33, 128.35, 132.90, 133.20, 135.66,
138.13.
1-Benzyloxymethyl-2-methylbenzene (2e)
IR (neat): 3029, 2857, 1496, 1454, 1359, 1072, 743, 697 cm–1.
1H NMR: d = 2.33 (s, 3 H), 4.55 (s, 2 H), 4.57 (s, 2 H), 7.15–7.38
(m, 9 H).
13C NMR: d = 18.88, 70.58, 72.28, 125.68, 127.54, 127.71, 127.75,
128.30, 128.62, 130.15, 136.04, 136.67, 138.26.
1-Cyclohexyloxy-3-phenylpropane (2u)
IR (neat): 2931, 2855, 1451, 1108, 699 cm–1.
1H NMR: d = 1.18–1.32 (m, 5 H), 1.49–1.55 (m, 1 H), 1.70–1.76 (m,
2 H), 1.84–1.92 (m, 4 H), 2.69 (t, J = 7.7 Hz, 2 H), 3.15–3.21 (m, 1
H), 3.44 (t, J = 6.4 Hz, 2 H), 7.13–7.28 (m, 5 H).
13C NMR: d = 24.26, 25.89, 31.74, 32.39, 32.44, 66.89, 77.44,
125.54, 128.13, 128.36, 142.03.
1-Benzyloxymethyl-3-methylbenzene (2f)
IR (neat): 3029, 2856, 1454, 1356, 1157, 779, 737, 696 cm–1.
1H NMR: d = 2.36 (s, 3 H), 4.52 (s, 2 H), 4.56 (s, 2 H), 7.09–7.39
(m, 9 H).
13C NMR: d = 21.44, 72.10, 72.13, 124.78, 127.51, 127.68, 128.20,
128.28, 128.44, 137.94, 138.07, 138.21.
References
(1) Greene, T. W.; Wuts, P. G. M. In Protective Groups in
Organic Synthesis, 3rd ed.; John Wiley & Sons: New York,
1999, 76.
1-Benzyloxymethyl-2,4,6-trimethylbenzene (2h)
IR (neat): 2917, 1453, 1070, 736, 697 cm–1.
(2) Watahiki, T.; Akabane, Y.; Mori, S.; Oriyama, T. Org. Lett.
1H NMR: d = 2.24 (s, 3 H), 2.32 (s, 6 H), 4.52 (s, 2 H), 4.55 (s, 2 H),
6.84 (s, 2 H), 7.26–7.38 (m, 5 H).
13C NMR: d = 19.58, 21.04, 66.25, 72.36, 127.49, 127.81, 128.25,
128.84, 131.14, 137.48, 137.80, 138.49.
2003, 5, 3045.
(3) Kato, J.; Iwasawa, N.; Mukaiyama, T. Chem. Lett. 1985,
743.
(4) (a) Sassaman, M. B.; Kotian, K. D.; Surya Prakash, G. K.;
Olah, G. A. J. Org. Chem. 1987, 52, 4314. (b) Hartz, N.;
SuryPrakash, G. K.; Olah, G. A. Synlett 1992, 569.
(5) Hatakeyama, S.; Mori, H.; Kitano, K.; Yamada, H.;
Nishizawa, M. Tetrahedron Lett. 1994, 35, 4367.
4-Benzyloxymethyl-1-bromobenzene (2j)
IR (neat): 3412, 1487, 1071, 1011 cm–1.
1H NMR: d = 4.50 (s, 2 H), 4.55 (s, 2 H), 7.22–7.49 (m, 9 H).
Synthesis 2005, No. 2, 183–186 © Thieme Stuttgart · New York