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P. C. B. Page
LETTER
equiv) was then added and the reaction mixture was stirred
overnight, poured into H2O and extracted with Et2O. The
combined ethereal layers were washed with brine, dried over
anhyd MgSO4 and concentrated to afford (R)-(–)-methyl
2-methoxy-2-phenylacetate (17.8 g, 98.7 mmol, 100%). IR:
Acknowledgment
We are indebted to the following for funding: EPSRC, Lough-
borough University and Secretaria de Estado de Educacion y
Universidades y Fondo Social Europeo.
n
max = 1740 cm–1. 1H NMR (400 MHz, CDCl3): d = 3.41 (s,
3 H), 3.72 (s, 3 H), 4.78 (s, 1 H), 7,34–7.45 (m, 5 H) ppm.
13C NMR (100 MHz, CDCl3): d = 52.7, 57.8, 82.9, 127.6,
129.1, 129.2, 136.6, 171.6 (C=O) ppm. [a]D –113 (c 1.0,
CHCl3). HPLC on ‘Chiracel OD-H’, eluting with hexane–
propan-2-ol 99:1.
References
(1) Nemoto, H.; Takamatsu, S.; Yamamoto, Y. J. Org. Chem.
1991, 56, 1321.
(2) Kalinowski, H.-O.; Crass, G.; Seebach, D. Chem. Ber. 1981,
114, 477.
(14) (a) IR: nmax = 1747 cm–1. 1H NMR (400 MHz, CDCl3): d =
1.54 (3 H, d, J = 6.9 Hz), 4.19 (1 H, q, J = 6.9 Hz), 4.53 and
4.77 (2 H, AB, J = 11.6 Hz), 5.27 and 5.28 (2 H, AB,
J = 12.3 Hz), 7.39–7.45 (10, m) ppm. 13C NMR (100 MHz,
CDCl3): d = 19.2 (Me), 66.5 (CH2), 72.0 (CH2), 74.1 (CH),
127.9 (CH), 128.1 (CH), 128.3 (CH), 128.4 (CH), 128.5
(CH), 128.7 (CH), 135.9 (C), 137.7 (C), 173.0 (C=O) ppm.
HRMS (FAB): m/z calcd for C17H19O3: 271.13393. Found:
271.13350 [M + 1]. [a]D –63.3 (c 1.6, CHCl3). (b) The
formation of racemic benzyl 2-benzyloxypropanoate has
been reported previously by photolysis of a chromium
carbene complex in the presence of carbon monoxide:
Bueno, A. B.; Moser, W. H.; Hegedus, L. S. J. Org. Chem.
1998, 63, 1462.
(3) Tsuji, R.; Arai, S.; Nishida, A. Synthesis 2004, 960.
(4) For example: (a) Aller, E.; Brown, D. S.; Cox, G. G.; Miller,
D. J.; Moody, C. J. J. Org. Chem. 1995, 60, 4449.
(b) Barluenga, J.; Vázquez-Villa, H.; Ballesteros, A.;
González, J. M. Org. Lett. 2002, 4, 2817. (c) Moreno-
Dorado, F. J.; Guerra, F. M.; Ortega, M. J.; Zubia, E.;
Massanet, G. M. Tetrahedron: Asymmetry 2003, 14, 503.
(5) (a) Valentine, D. Jr.; Johnson, K. K.; Priester, W.; Sun, R.
C.; Toth, K.; Saucy, G. J. Org. Chem. 1980, 45, 3698.
(b) Colombo, L.; Gennari, C.; Scolastico, C.; Guanti, G.;
Narisano, E. J. Chem. Soc., Perkin Trans. 1 1981, 1278.
(c) Higgins, S. D.; Thomas, C. B. J. Chem. Soc., Perkin
Trans. 1 1982, 235.
(15) n-BuLi (3.7 mL, 9.25 mmol, 2.2 equiv) was added slowly to
dry DMSO (7 mL) under nitrogen in a dry 25 mL round-
bottomed flask. 2-Hydroxy-3-methylbutanoic acid (500 mg,
4.23 mmol, 1 equiv) in DMSO (7 mL) was then added. The
solution was stirred during 2 h before MeI (630 mL, 10.16
mmol, 2.40 equiv) was added slowly. The reaction mixture
was allowed to stir overnight and H2O (50 mL) and Et2O (20
mL) were then added to the mixture. The organic phase was
separated, washed with brine, dried over Na2SO4 and
concentrated under reduced pressure to afford the methyl
2-methoxy-3-methylbutanoate as a pale yellow liquid (620
mg, 100%). IR: nmax = 1750 cm–1. 1H NMR (400 MHz,
CDCl3): d = 0.86 (d, 3 H, J = 5.0 Hz), 0.88 (d, 3 H, J = 5.0
Hz), 1.96 (m, 1 H), 3.30 (s, 3 H), 3.44 (d, 1 H, J = 5.4 Hz),
and 3.68 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): d =
17.5 (Me), 18.5 (Me), 31.5 (CH), 51.4 (Me), 58.4 (Me), 95.9
(CH), 172.7 (C=O) ppm. HRMS (EI): m/z calcd for C7H14O3:
146.09430. Found: 146.09460.
(6) (a) Sakamoto, T.; Kondo, Y.; Masumoto, K.; Yamanaka, H.
J. Chem. Soc., Perkin Trans. 1 1994, 235. (b) Moriarty, R.
M.; Rani, N.; Condeiu, C.; Duncan, M. P.; Prakash, O. Synth.
Commun. 1997, 27, 3273. (c) Ogura, K.; Watanabe, J.-I.;
Takahashi, K.; Iida, H. J. Org. Chem. 1982, 47, 4504.
(d) Bonner, W. A. J. Am. Chem. Soc. 1951, 73, 3126.
(e) Annunziata, R.; Cinquini, M.; Cozzi, F.; Gilardi, A.;
Cardani, S.; Poli, G.; Scolastico, C. J. Chem. Soc., Perkin
Trans. 1 1985, 255. (f) Dueno, E. E.; Chu, F.; Kim, S.-I.;
Jung, K. W. Tetrahedron Lett. 1999, 40, 1843. (g) Kimura,
M.; Kuboki, A.; Sigai, T. Tetrahedron: Asymmetry 2002, 13,
1059. (h) Confalone, P. N.; Ko, S. S. Tetrahedron Lett. 1984,
25, 947. (i) Ramig, K.; Englander, M.; Kallashi, F.; Livchits,
L.; Zhou, J. Tetrahedron Lett. 2002, 43, 7731. (j) Dueno, E.
E.; Chu, F.; Kim, S.-I.; Jung, K. Q. Tetrahedron Lett. 1999,
40, 1843.
(7) (a) Gung, B. W.; Wolf, M. A. J. Org. Chem. 1993, 58, 7038.
(b) Sutherland, A.; Willis, C. L. Tetrahedron Lett. 1997, 38,
1837.
(8) Jackson, W. R.; Jacobs, H. A.; Jayatilake, G. S.; Matthews,
B. R.; Watson, K. G. Aust. J. Chem. 1990, 43, 2045.
(9) (a) Heaney, H.; Ley, S. V. J. Chem. Soc., Perkin Trans. 1
1973, 499. (b) Heaney, H.; Ley, S. V. Org. Synth. 1974, 54,
58.
(10) (a) Corey, E. J.; Chaykovsky, M. J. Am. Chem. Soc. 1962,
84, 866. (b) Corey, E. J.; Chaykovsky, M. J. Am. Chem. Soc.
1965, 87, 1345.
(11) (a) Kriz, J.; Benes, M. J.; Peska, J. Tetrahedron Lett. 1965,
2881. (b) Kriz, J.; Benes, M. J.; Peska, J. Collect. Czech.
Chem. Commun. 1967, 32, 398.
(12) (a) Corey, E. J.; Chaykovsky, M. J. Am. Chem. Soc. 1964,
86, 1639. (b) Becker, H.-D.; Mikol, G. J.; Russell, G. A. J.
Am. Chem. Soc. 1963, 85, 3410. (c) Stetter, H.; Hesse, R.
Monatsh. Chem. 1967, 98, 755.
(13) A hexane solution of n-BuLi (83 mL, 207.0 mmol, 2.5 M.
2.1 equiv) was added carefully to anhyd DMSO (150 mL) in
a 500 mL round-bottomed flask. (R)-(–)-Mandelic acid (15
g, 98.7 mmol) was added and the resulting solution was
stirred under nitrogen for 2 h. MeI (32.2 g, 227.0 mmol, 2.3
(16) IR: nmax = 1745 cm–1. 1H NMR (400 MHz, CDCl3): d = 0.82
(3 H, d, J = 6.9 Hz), 0.84 (3 H, d, J = 6.8 Hz), 1.99 (1 H, m),
3.61 (1 H, d, J = 5.5 Hz), 4.23 and 4.55 (2 H, AB, J = 11.7
Hz), 5.04 and 5.06 (2 H, AB, J = 12.2 Hz),7.19–7.22 (10 H,
m) ppm. 13C NMR (100 MHz, CDCl3): d = 17.8 (Me), 18.9
(Me), 31.7 (CH), 66.4 (CH2), 72.5 (CH2), 83.3 (CH), 127.8
(CH), 128.1 (CH), 128.3 (8) (CH), 128.4 (2) (CH), 128.5
(CH), 128.6 (CH), 135.9 (C), 137.8 (C), and 172.3 (C=O)
ppm. HRMS (FAB): m/z calcd for C17H19O3: 299.16443.
Found: 299.16406 [M + 1].
(17) IR: nmax = 1736 cm–1. 1H NMR (400 MHz, CDCl3): d = 1.18
(3 H, d, J = 6.2 Hz), 2.40 and 2.61 (2 H, o, AB of ABX,
JA-B = –15.09 Hz, JA-X = 7.52 Hz, JB-X = 5.51 Hz), 3.95 (1 H,
q × q, J = 6.2, 5.51, 7.52 Hz), 4.39 and 4.45 (2 H, AB,
J = 11.6 Hz), 5.04 and 5.05 (2 H, AB, J = 12.3 Hz), and
7.23–7.26 (10 H, m) ppm. 13C NMR (100 MHz, CDCl3):
d = 19.9 (Me), 42.2 (CH2), 66.4 (CH2), 70.9 (CH2), 72.2
(CH), 127.5 (CH), 127.7 (CH), 128.2 (CH), 128.2 (5) (CH),
128.3 (CH), 128.6 (CH), 136.0 (C), 138.5 (C), 171.3 (C=O)
ppm. HRMS (FAB): m/z calcd for C18H21O3 285.14907.
Found: 285.14941 [M + 1].
Synlett 2004, No. 14, 2606–2608 © Thieme Stuttgart · New York