References and Notes
<A NAME="RU13806ST-1A">1a </A>
Mehta G.
Singh SR.
Angew. Chem. Int. Ed.
2006,
45:
953
<A NAME="RU13806ST-1B">1b </A>
Facundo VA.
Sa AL.
Silva SAF.
Morais SM.
Matos CRR.
Braz-Filho R.
J. Braz. Chem. Soc.
2004,
15:
140
<A NAME="RU13806ST-1C">1c </A>
Ciufolini MA.
Zhu S.
J. Org. Chem.
1998,
63:
1668
<A NAME="RU13806ST-1D">1d </A>
Smith AB.
Branca SJ.
Pilla NN.
Guaciaro MA.
J. Org. Chem.
1982,
47:
1855
<A NAME="RU13806ST-2A">2a </A> For recent example, see:
Arnold LA.
Naasz R.
Minnaard AJ.
Feringa BL.
J. Org. Chem.
2002,
67:
7244 ; and references cited therein
<A NAME="RU13806ST-2B">2b </A>
Aoyama Y.
Konoike T.
Kanda A.
Naya N.
Nakajima M.
Bioorg. Med. Chem. Lett.
2001,
11:
1695
<A NAME="RU13806ST-2C">2c </A>
Nagasawa H,
Utsu Y, and
Hori H. inventors; Jpn. Kokai Tokkyo Koho, JP2006151879.
<A NAME="RU13806ST-2D">2d </A>
Hori H.
Nagasawa H.
Ishibashi M.
Uto Y.
Hirata A.
Saijo K.
Ohkura K.
Kirk KL.
Uehara Y.
Bioorg. Med. Chem.
2002,
10:
3257
<A NAME="RU13806ST-3A">3a </A>
Handbook of Organopalladium Chemistry for Organic Synthesis
Vol. 2:
Negishi E.
Wiley;
New York:
2002.
p.2309
For recent reviews, see:
<A NAME="RU13806ST-3B">3b </A>
Nakamura I.
Yamamoto Y.
Chem. Rev.
2004,
104:
2127
<A NAME="RU13806ST-3C">3c </A>
Zeni G.
Larock RC.
Chem. Rev.
2004,
104:
2285
<A NAME="RU13806ST-3D">3d </A>
Alonso F.
Beletskaya IP.
Yus M.
Chem. Rev.
2004,
104:
3079
<A NAME="RU13806ST-3E">3e </A>
Tietze LF.
Ila H.
Bell HP.
Chem. Rev.
2004,
104:
3453
<A NAME="RU13806ST-3F">3f </A>
Soderberg BCG.
Coord. Chem. Rev.
2004,
248:
1085
<A NAME="RU13806ST-3G">3g </A>
Vizer SA.
Yerzhanov KB.
Quntar AAAA.
Dembitsky VM.
Tetrahedron
2004,
60:
5499
<A NAME="RU13806ST-3H">3h </A>
Muzart J.
Tetrahedron
2005,
61:
5955
For recent reviews of Pauson-Khand reaction, see:
<A NAME="RU13806ST-4A">4a </A>
Blanco-Urgoiti J.
Anorbe L.
Perez-Serrano L.
Dominguez G.
Perez-Castells J.
Chem. Soc. Rev.
2004,
33:
32
<A NAME="RU13806ST-4B">4b </A>
Bonaga LV.
Krafft ME.
Tetrahedron
2004,
60:
9795
<A NAME="RU13806ST-4C">4c </A>
Gibson SE.
Lewis SE.
Mainolfi N.
J. Organomet. Chem.
2004,
689:
3873
<A NAME="RU13806ST-4D">4d </A>
Gibson SE.
Stevenazzi A.
Angew. Chem. Int. Ed.
2003,
42:
1800
For recent examples of transition-metal-catalyzed related reactions, see:
<A NAME="RU13806ST-4E">4e </A>
Sherry BD.
Maus L.
Laforteza BN.
Toste FD.
J. Am. Chem. Soc.
2006,
128:
8132
<A NAME="RU13806ST-4F">4f </A>
Liu Z.
Wasmuth AS.
Nelson SG.
J. Am. Chem. Soc.
2006,
128:
10352
<A NAME="RU13806ST-4G">4g </A>
Lo C.-Y.
Lin C.-C.
Cheng H.-M.
Liu R.-S.
Org. Lett.
2006,
8:
3153
<A NAME="RU13806ST-4H">4h </A>
Simmons EM.
Sarpong R.
Org. Lett.
2006,
8:
2883
<A NAME="RU13806ST-4I">4i </A>
Sun J.
Conley MP.
Zhang L.
Kozmin SA.
J. Am. Chem. Soc.
2006,
128:
9705
<A NAME="RU13806ST-4J">4j </A>
Lian J.-J.
Lin C.-C.
Chang H.-K.
Chen P.-C.
Liu R.-S.
J. Am. Chem. Soc.
2006,
128:
9661
<A NAME="RU13806ST-4K">4k </A>
Luzung MR.
Markham JP.
Toste FD.
J. Am. Chem. Soc.
2004,
126:
10858
<A NAME="RU13806ST-4L">4l </A>
Jimenez-Nunez E.
Claverie CK.
Nieto-Oberhuber C.
Echavarren AM.
Angew. Chem. Int. Ed.
2006,
45:
5452
<A NAME="RU13806ST-4M">4m </A>
Hashmi ASK.
Angew. Chem. Int. Ed.
2005,
44:
6990
<A NAME="RU13806ST-4N">4n </A>
Ojima I.
Lee S.-Y.
J. Am. Chem. Soc.
2000,
122:
2385
<A NAME="RU13806ST-5A">5a </A>
Tamao K.
Yamaguchi S.
Shiro M.
J. Am. Chem. Soc.
1994,
116:
11715
<A NAME="RU13806ST-5B">5b </A>
Tamao K.
Yamaguchi S.
J Chem. Soc., Dalton Trans.
1998,
3693
<A NAME="RU13806ST-5C">5c </A>
Wrackmeyer B.
Suβ J.
Z. Naturforsch., B: Chem. Sci.
2002,
57:
741
<A NAME="RU13806ST-5D">5d </A>
Takahashi T.
Xi Z.
Obora Y.
Suzuki N.
J. Am. Chem. Soc.
1995,
117:
2665
<A NAME="RU13806ST-6A">6a </A>
Marion N.
Diez-Gonzalez S.
Fremont P.
Noble AR.
Nolan SP.
Angew. Chem. Int. Ed.
2006,
45:
3647
<A NAME="RU13806ST-6B">6b </A>
Wang S.
Zhang L.
J. Am. Chem. Soc.
2006,
128:
8414
<A NAME="RU13806ST-6C">6c </A>
Pujanauski BG.
Prasad BAB.
Sarpong R.
J. Am. Chem. Soc.
2006,
128:
6786
<A NAME="RU13806ST-6D">6d </A>
Zhang L.
Wang S.
J. Am. Chem. Soc.
2006,
128:
1442
<A NAME="RU13806ST-6E">6e </A>
Zhao J.
Hughes CO.
Toste FD.
J. Am. Chem. Soc.
2006,
128:
7436
<A NAME="RU13806ST-6F">6f </A>
Zhang L.
J. Am. Chem. Soc.
2005,
127:
16804
<A NAME="RU13806ST-6G">6g </A>
Johansson MJ.
Gorin DJ.
Staben ST.
Toste FD.
J. Am. Chem. Soc.
2005,
127:
18002
<A NAME="RU13806ST-6H">6h </A>
Prasad BAB.
Yoshimoto FK.
Sarpong R.
J. Am. Chem. Soc.
2005,
127:
12468
<A NAME="RU13806ST-6I">6i </A>
Miki K.
Uemura S.
Ohe K.
Chem. Lett.
2005,
34:
1068
<A NAME="RU13806ST-6J">6j </A>
Shi X.
Gorin DJ.
Toste FD.
J. Am. Chem. Soc.
2005,
127:
5802
<A NAME="RU13806ST-6K">6k </A>
Cariou K.
Mainetti E.
Fensterbank L.
Malacria M.
Tetrahedron
2004,
60:
9745
<A NAME="RU13806ST-6L">6l </A>
Mamane V.
Gress T.
Krause H.
Fürstner A.
J. Am. Chem. Soc.
2004,
126:
8654
<A NAME="RU13806ST-6M">6m </A> Recently, we have reported ‘A Gold(III)-Catalyzed Double Wacker-type Reaction
of 1,1-Diethynyl Acetate’:
Kato K.
Teraguchi R.
Kusakabe T.
Motodate S.
Yamamura S.
Mochida T.
Akita H.
Synlett
2007,
63
<A NAME="RU13806ST-7A">7a </A>
Rautenstrauch V.
J. Org. Chem.
1984,
49:
950
<A NAME="RU13806ST-7B">7b </A>
Kataoka H.
Watanabe K.
Goto K.
Tetrahedron Lett.
1990,
31:
4181
<A NAME="RU13806ST-7C">7c </A>
Mahrwald R.
Schick H.
Angew. Chem., Int. Ed. Engl.
1991,
30:
593
<A NAME="RU13806ST-7D">7d </A>
Bartels A.
Mahrwald R.
Müller K.
Adv. Synth. Catal.
2004,
346:
483
<A NAME="RU13806ST-7E">7e </A>
Vijaykumar D.
Mao W.
Kirschbaum KS.
Katzenellenbogen JA.
J. Org. Chem.
2002,
67:
4904
<A NAME="RU13806ST-7F">7f </A>
Kato K.
Yamamoto Y.
Akita H.
Tetrahedron Lett.
2002,
43:
6587
<A NAME="RU13806ST-7G">7g </A>
Kato K.
Nouchi H.
Ishikura K.
Takaishi S.
Motodate S.
Tanaka H.
Okudaira K.
Mochida T.
Nishigaki R.
Shigenobu K.
Akita H.
Tetrahedron
2006,
62:
2545
<A NAME="RU13806ST-8A">8a </A>
Kato K.
Nishimura A.
Yamamoto Y.
Akita H.
Tetrahedron Lett.
2001,
42:
4203
<A NAME="RU13806ST-8B">8b </A>
Takayama H.
Kato K.
Akita H.
Eur. J. Org. Chem.
2006,
644
<A NAME="RU13806ST-8C">8c </A>
Kato K.
Yamamoto Y.
Akita H.
Tetrahedron Lett.
2002,
43:
4915
<A NAME="RU13806ST-8D">8d </A>
Kato K.
Tanaka M.
Yamamoto Y.
Akita H.
Tetrahedron Lett.
2002,
43:
1511
<A NAME="RU13806ST-8E">8e </A>
Kato K.
Tanaka M.
Yamamura S.
Yamamoto Y.
Akita H.
Tetrahedron Lett.
2003,
44:
3089
<A NAME="RU13806ST-8F">8f </A>
Kato K.
Matsuba C.
Kusakabe T.
Takayama H.
Yamamura S.
Mochida T.
Akita H.
Peganova TA.
Vologdin NV.
Gusev OV.
Tetrahedron
2006,
62:
9988
<A NAME="RU13806ST-9A">9a </A>
Crosignani S.
Desimoni G.
Faita G.
Righetti PP.
Tetrahedron
1998,
54:
15721
<A NAME="RU13806ST-9B">9b </A>
Hansen KB.
Finney NS.
Jacobsen EN.
Angew. Chem. Int. Ed.
1995,
34:
676
<A NAME="RU13806ST-9C">9c </A>
The Phbox ligands 10 and (±)-4 were prepared as easily separable mixture by the condensation of racemic phenyl glycinol
with dimethylmalonyl dichloride. See:
<A NAME="RU13806ST-9D">9d </A>
Lee S.
Lee WM.
Sulikowski GA.
J. Org. Chem.
1999,
64:
4224
<A NAME="RU13806ST-10A">10a </A>
Pearson RG.
J. Am. Chem. Soc.
1963,
85:
3533
<A NAME="RU13806ST-10B">10b </A>
Gemal AL.
Luche JL.
J. Am. Chem. Soc.
1981,
103:
5454
<A NAME="RU13806ST-11">11 </A>
General Procedure for the Reaction of 1.
A 30 mL two-necked round-bottomed flask, containing a magnetic stirring bar, Pd(TFA)2 (0.015 mmol), ligand (0.0225 mmol), p -benzoquinone (0.6 mmol) and MeOH (5 mL) was fitted with a rubber septum and a three-way
stopcock connected to a balloon filled with CO. The apparatus was purged with CO by
pumping-filling via the three-way stopcock. To the stirred solution the substrate
1 (0.3 mmol) was added dropwise (3 × 1 mL) via a syringe at 0 °C. After being stirred
for a certain period at the appropriate temperature, the mixture was diluted with
CH2 Cl2 (30 mL), and washed with 2% Na2 SO3 aq (30 mL). The organic layers were separated, the aqueous layer was extracted with
CH2 Cl2 (30 mL), and the combined organic layers were dried with MgSO4 and concentrated in vacuo. The crude product was purified by column chromatography
on silica gel. The fraction eluted with hexane-EtOAc (100:1 to 50:1) afforded 2 and 3 (10:1). The products 2 were separated to give each diastereomer by preparative TLC. The ee of each diastereomer
was determined by HPLC using Chiralcel OD column (hexane-EtOH = 150:1, FL = 1.0, for
3a-2 ) and Chiralcel OF column (hexane-EtOH = 150:1, FL = 0.5, for 3a-1 ). The relative stereochemistry of 3 was estimated as shown in Figure
[2 ]
, based on NOE experiments. Compound 2a : slightly yellow needles; mp 56 °C. 1 H NMR (CDCl3 ): δ = 2.80-2.84 (2 H, m), 2.89 (2 H, s), 2.95-2.99 (2 H, m), 3.44 (6 H, s), 5.35
(1 H, s), 7.18-7.31 (5 H, m). 13 C NMR (CDCl3 ): δ = 26.5, 34.4, 41.1, 55.5, 98.7, 126.3, 128.4, 128.5, 141.0, 152.3, 161.4, 198.8,
200.3. MS-FAB: m/z = 275 [M+ + H]. IR (KBr): 2933, 1742, 1706 cm-1 . Anal. Calcd (%) for C16 H18 O4 : C, 70.06; H, 6.61. Found: C, 69.86; H, 6.57. Compound 3a-1 (more polar diastereomer): colorless needles; mp 44 °C. 1 H NMR (CDCl3 ): δ = 1.71 (3 H, s), 2.24-2.30 (1 H, m), 2.72 (1 H, s), 2.77-2.90 (2 H, m), 2.95-3.04
(1 H, m), 3.39 (3 H, s), 3.70 (3 H, s), 5.50 (1 H, s), 7.16-7.30 (5 H, m). 13 C NMR (CDCl3 ): δ = 24.1, 30.2, 40.2, 50.3, 51.2, 74.5, 79.5, 81.5, 91.0, 124.2, 126.1, 128.5,
128.5, 141.0, 165.9, 168.0. HRMS (EI): m/z [M+ ] calcd for C18 H20 O5 : 316.1311; found: 316.1304. IR (KBr): 3269, 2950, 2121, 1720, 1666 cm-1 . Compound 3a-2 (less polar diastereomer): colorless needles; mp 35 °C. 1 H NMR (CDCl3 ): δ = 1.76 (3 H, s), 2.18-2.27 (1 H, m), 2.71 (1 H, s), 2.84-2.92 (1 H, m), 3.03-3.12
(2 H, m), 3.45 (3 H, s), 3.69 (3 H, s), 5.47 (1 H, s), 7.21-7.28 (5 H, m). 13 C NMR (CDCl3 ): δ = 24.0, 30.5, 39.3, 49.6, 51.2, 74.6, 80.0, 80.3, 91.1, 124.5, 126.1, 128.5,
128.5, 141.2, 166.0, 167.4. HRMS (EI): m/z [M+ ] calcd for C18 H20 O5 : 316.1311; found 316.1318. IR (KBr): 3246, 2949, 2113, 1708, 1658 cm-1 . Compound 2b : slightly yellow oil. 1 H NMR (CDCl3 ): δ = 0.88 (3 H, t, J = 6.8 Hz), 1.22-1.56 (12 H, m), 2.65 (2 H, t, J = 7.8 Hz), 2.89 (2 H, s), 3.45 (6 H, s), 5.36 (1 H, s). 13 C NMR (CDCl3 ): δ = 14.1, 22.7, 24.4, 28.4, 29.1, 29.2, 30.0, 31.8, 41.2, 55.5, 98.8, 151.7, 162.8,
198.9, 200.7. HRMS (EI): m/z [M+ ] calcd for C16 H26 O4 : 282.1831; found: 282.1829. IR (neat): 2927, 1745, 1706 cm-1 . Compound 3b-1 (more polar diastereomer): colorless oil. 1 H NMR (CDCl3 ): δ = 0.88 (3 H, t, J = 8.0 Hz), 1.22-1.35 (10 H, m), 1.39-1.52 (1 H, m), 1.57-1.71 (1 H, m), 1.68 (3 H,
s), 1.99-2.06 (1 H, m), 2.41-2.49 (1 H, m), 2.66 (1 H, s), 3.36 (3 H, s), 3.70 (3
H, s), 5.47 (1 H, s). 13 C NMR (CDCl3 ): δ = 14.1, 22.7, 23.8, 24.1, 29.2, 29.3, 29.4, 31.9, 38.4, 50.3, 51.1, 74.1, 79.9,
82.1, 90.6, 124.0, 165.9, 168.4. HRMS (EI): m/z [M+ ] calcd for C18 H28 O5 : 324.1937; found: 324.1924. IR (KBr): 3281, 2927, 2120, 1723, 1657 cm-1 . Compound 3b-2 (less polar diastereomer): colorless oil. 1 H NMR (CDCl3 ): δ = 0.88 (3 H, t, J = 7.0 Hz), 1.22-1.40 (10 H, m), 1.49-1.62 (1 H, m), 1.68-1.78 (1 H, m), 1.72 (3 H,
s), 1.93-2.00 (1 H, m), 2.64-2.72 (1 H, m), 2.65 (1 H, s), 3.31 (3 H, s), 3.70 (3
H, s), 5.45 (1 H, s). 13 C NMR (CDCl3 ): δ = 14.1, 22.7, 24.1, 24.1, 29.2, 29.4, 29.5, 31.9, 37.4, 49.5, 51.1, 74.2, 80.4,
80.8, 90.8, 124.3, 166.0, 167.9. HRMS (EI): m/z [M+ ] calcd for C18 H28 O5 : 324.1937; found: 324.1965. IR (KBr): 3296, 2931, 2119, 1725, 1657 cm-1 . Compound 2c : colorless oil. 1 H NMR (CDCl3 ): δ = 0.90 (3 H, t, J = 7.2 Hz), 1.31-1.37 (4 H, m), 1.47-1.54 (2 H, m), 2.65 (2 H, t, J = 7.8 Hz), 2.89 (2 H, s), 3.45 (6 H, s), 5.37 (1 H, s). 13 C NMR (CDCl3 ): δ = 13.9, 22.3, 24.3, 28.1, 32.1, 41.2, 55.5, 98.7, 151.7, 162.8, 199.0, 200.7.
HRMS (EI): m/z [M+ ] calcd for C13 H20 O4 : 240.1362; found: 240.1352. IR (neat): 2932, 1745, 1706 cm-1 . Compound 3c-1 (more polar diastereomer): colorless oil. 1 H NMR (CDCl3 ): δ = 0.89 (3 H, t, J = 7.2 Hz), 1.29-1.37 (4 H, m), 1.44-1.52 (1 H, m), 1.58-1.66 (1 H, m), 1.69 (3 H,
s), 1.98-2.06 (1 H, m), 2.40-2.49 (1 H, m), 2.67 (1 H, s), 3.36 (3 H, s), 3.70 (3
H, s), 5.47 (1 H, s). 13 C NMR (CDCl3 ): δ = 13.9, 22.4, 23.4, 24.0, 31.4, 38.3, 50.2, 51.1, 74.1, 79.8, 82.0, 90.6, 124.0,
165.9, 168.4. HRMS (EI): m/z [M+ ] calcd for C15 H22 O5 : 282.1467; found: 282.1419. IR (KBr): 3248, 2952, 2122, 1710, 1656 cm-1 . Anal. Calcd for C15 H22 O5 : C, 63.83; H, 7.85. Found: C, 63.71; H, 7.89. Compound 3c-2 (less polar diastereomer): colorless oil. 1 H NMR (CDCl3 ): δ = 0.90 (3 H, t, J = 6.8 Hz), 1.31-1.37 (4 H, m), 1.51-1.61 (1 H, m), 1.68-1.79 (1 H, m), 1.73 (3 H,
s), 1.92-2.00 (1 H, m), 2.65-2.72 (1 H, m), 2.65 (1 H, s), 3.31 (3 H, s), 3.70 (3
H, s), 5.45 (1 H, s). 13 C NMR (CDCl3 ): δ = 13.9, 22.5, 23.7, 24.0, 31.5, 37.3, 49.5, 51.1, 74.2, 80.4, 80.8, 90.8, 124.3,
166.0, 167.9. HRMS (EI): m/z [M+ ] calcd for C15 H22 O5 : 282.1467; found: 282.1466. IR (KBr): 3298, 2952, 2120, 1723, 1658 cm-1 . Compound 2d : colorless oil. 1 H NMR (CDCl3 ): δ = 1.41 (3 H, s), 2.93 (2 H, s), 3.09 (2 H, s), 3.49 (6 H, s), 3.91-3.99 (4 H,
m), 5.39 (1 H, s). 13 C NMR (CDCl3 ): δ = 25.2, 32.7, 41.6, 56.1, 64.8, 100.1, 109.3, 153.1, 156.5, 198.5, 199.9. HRMS
(EI): m/z [M+ ] calcd for C13 H18 O6 : 270.1103; found: 270.1109. IR (neat): 3438, 2937, 1750, 1708 cm-1 . Compound 3d : inseparable mixture of diastereomers (ratio = 2.4:1); colorless oil. 1 H NMR (CDCl3 ): δ (major diastereomer) = 1.56 (3 H, s), 1.73 (3 H, s), 2.44 (1 H, d, J = 15.2 Hz), 2.71 (1 H, s), 2.96 (1 H, d, J = 15.2 Hz), 3.38 (3 H, s), 3.70 (3 H, s), 3.87-4.08 (4 H, m), 5.46 (1 H, s). 1 H NMR (CDCl3 ): δ = (minor diastereomer) = 1.61 (3 H, s), 1.76 (3 H, s), 2.18 (1 H, d, J = 14.8 Hz), 2.72 (1 H, s), 3.32 (1 H, d, J = 14.8 Hz), 3.35 (3 H, s), 3.70 (3 H, s), 3.87-4.08 (4 H, m), 5.43 (1 H, s). 13 C NMR (CDCl3 ): δ (major diastereomer) = 23.7, 25.9, 44.9, 50.4, 51.1, 64.3, 64.5, 74.2, 79.1,
79.9, 90.1, 108.2, 124.5, 165.9, 168.8. 13 C NMR (CDCl3 ): δ (minor diastereomer) = 24.1, 25.5, 43.9, 49.6, 51.1, 64.4, 64.5, 74.7, 77.9,
80.1, 90.3, 108.5, 125.2, 165.9, 168.5. HRMS (EI): m/z [M+ ] calcd for C15 H20 O7 : 312.1209; found: 312.1191. IR (KBr): 3248, 2907, 2117, 1707, 1650 cm-1 .
Compound 2e : colorless oil. 1 H NMR (CDCl3 ): δ = 2.88 (2 H, s), 3.45 (6 H, s), 4.04 (2 H, s), 5.43 (1 H, s), 7.17-7.35 (5 H,
m). 13 C NMR (CDCl3 ): δ = 30.0, 41.3, 55.6, 98.7, 126.7, 128.5, 129.6, 136.6, 151.8, 159.6, 198.8, 200.3.
HRMS (EI): m/z [M+ ] calcd for C16 H16 O4 : 260.1049; found: 260.1054. IR (KBr): 2935, 1747, 1706 cm-1 .
Compound 3e-1 (more polar diastereomer): colorless needles; mp 64 °C. 1 H NMR (CDCl3 ): δ = 1.23 (3 H, s), 2.70 (1 H, s), 3.33 (3 H, s), 3.54 (1 H, d, J = 14.0 Hz), 3.78 (3 H, s), 3.81 (1 H, d, J = 14.0 Hz), 5.54 (1 H, s), 7.23-7.30 (5 H, m). 13 C NMR (CDCl3 ): δ = 23.3, 43.9, 50.4, 51.3, 74.7, 80.2, 82.1, 91.3, 124.4, 127.4, 128.0, 131.3,
134.6, 166.1, 167.6 MS (EI): m/z = 302 [M+ ]. IR (KBr): 3262, 2115, 1716, 1657 cm-1 . Anal. Calcd for C17 H18 O5 : C, 67.54; H, 6.00. Found: C, 67.63; H, 6.05. Compound 3e-2 (less polar diastereomer): colorless needles; mp 67 °C. 1 H NMR (CDCl3 ): δ = 1.70 (3 H, s), 2.65 (1 H, s), 3.05 (3 H, s), 3.61 (1 H, d, J = 14.0 Hz), 3.77 (3 H, s), 3.87 (1 H, d, J = 14.0 Hz), 5.55 (1 H, s), 7.25-7.38 (5 H, m). 13 C NMR (CDCl3 ): δ = 24.1, 42.7, 49.5, 51.3, 75.2, 80.3, 80.4, 91.5, 124.5, 127.2, 128.0, 131.2,
135.0, 166.2, 167.2. MS (EI): m/z = 302 [M+ ]. IR (KBr): 3262, 2117, 1716, 1651 cm-1 . Anal. Calcd for C17 H18 O5 : C, 67.54; H, 6.00. Found: C, 67.19; H, 6.02.
Figure 2