References and Notes
<A NAME="RG10706ST-1A">1a</A>
Richecœur AME.
Sweeney J.
Tetrahedron
2000,
56:
389
<A NAME="RG10706ST-1B">1b</A>
Hollingworth GJ.
Richecœur AME.
Sweeney J.
J. Chem. Soc., Perkin Trans. 1
1996,
2833
<A NAME="RG10706ST-1C">1c</A>
Hollingworth GJ.
Perkins G.
Sweeney J.
J. Chem. Soc., Perkin Trans. 1
1996,
1913
<A NAME="RG10706ST-2">2</A>
Carter NB.
Mabon R.
Richecœur AME.
Sweeney JB.
Tetrahedron
2002,
58:
9117
For other routes to 3,4-disubstituted furanones, see, for instance:
<A NAME="RG10706ST-3A">3a</A>
Rossi R.
Bellina F.
Raugei E.
Synlett
2000,
1749
<A NAME="RG10706ST-3B">3b</A>
Forgione P.
Wilson PD.
Fallis AG.
Tetrahedron Lett.
2000,
41:
17
<A NAME="RG10706ST-3C">3c</A>
Duboudin JG.
Jousseaume B.
J. Organomet. Chem.
1979,
168:
233
<A NAME="RG10706ST-3D">3d</A>
Mornet R.
Gouin L.
Bull. Soc. Chim. Fr.
1977,
737
<A NAME="RG10706ST-3E">3e</A>
Crisp GT.
Meyer AG.
J. Org. Chem.
1992,
57:
6972
<A NAME="RG10706ST-3F">3f</A>
Wakharkar RD.
Deshpande VH.
Landge AB.
Upadhye BK.
Synth. Commun.
1987,
17:
1513
<A NAME="RG10706ST-3G">3g</A>
Okazaki R.
Negishi Y.
Inamoto N.
J. Org. Chem.
1989,
49:
3819
<A NAME="RG10706ST-3H">3h</A>
Delaunay J.
Orliac-Le Moing A.
Simonet J.
Tetrahedron
1988,
44:
3819
<A NAME="RG10706ST-3I">3i</A>
Boukouvalas J.
Maltais F.
Lachance N.
Tetrahedron Lett.
1994,
35:
7897 ; and references therein
<A NAME="RG10706ST-4">4</A>
It is not possible to directly discern the yields of the individual coupling reactions:
assuming a maximum yield of 100% for the second coupling (normally a more efficient
process, see ref. 2), the maximum possible yield for the first step is 51%. Our original
observations in monocoupling of 1 with PhI gave 2 (Ar = Ph) in a yield of 51%.
<A NAME="RG10706ST-5">5</A>
Representative Experimental Procedure.
To a flame-dried flask (under argon atmosphere) charged with PdCl2(PPh3)2 (2 mol%), CuI (8 mol%), AsPh3 (8 mol%) was added 3,4-bis(tributylstannyl)furan-2(5H)-one (500 mg, 0.76 mmol) as a solution in dry, deoxygenated DMF, followed by iodobenzene
(310 mg, 1.52 mmol), also added dropwise as a solution in DMF (2.0 mL). After reaction
was complete (24 h) the mixture was diluted with aq KF (1 M, 10.0 mL) and extracted
with Et2O (3 × 30.0 mL), washed with H2O (3 × 15.0 mL) and brine (3 × 15.0 mL). Solvent was removed under reduced pressure
and the crude product was purified via flash chromatography (silica gel, 3:2 PE-Et2O; R
f
= 0.24). Recrystallization (CH2Cl2-PE) gave 3,4-diphenylfuran-2(5H)-one as pale yellow crystals (56%, 101 mg); mp 104-105 °C (CH2Cl2-PE). IR (CHCl3): 1751, 1646, 1489 cm-1. 1H NMR (250 MHz, CDCl3): δ = 5.10 (2 H, s), 7.23-7.33 (10 H, m). 13C NMR (60 MHz, CDCl3): δ = 71.0 (OCH2), 126.6, 127.9, 129.2, 129.3, 129.4, 129.7, 130.6, 131.0, 131.2, 156.6, 173.9. MS
(CI, NH3): m/z calcd for C16H13O2: 237.0916. Found [MH]+: 237.0915; m/z (%) = 179.0 (15).
See, for instance:
<A NAME="RG10706ST-6A">6a</A>
Higuchi K.
Sawada K.
Nambu H.
Shogaki T.
Kita Y.
Org. Lett.
2003,
5:
3703
<A NAME="RG10706ST-6B">6b</A>
Wang L.
Pan Y.
Jiang X.
Hu H.
Tetrahedron Lett.
2000,
41:
725
<A NAME="RG10706ST-6C">6c</A>
Kumar P.
Org. Prep. Proced. Int.
1997,
29:
477
<A NAME="RG10706ST-6D">6d</A>
Pan Y.
Zhang Z.
Hu H.
Synthesis
1995,
245
<A NAME="RG10706ST-6E">6e</A>
Pan Y.
Zang Z.
Hu H.
Synth. Commun.
1992,
22:
2019
<A NAME="RG10706ST-6F">6f</A>
Hashem MA.
Weyerstahl P.
Tetrahedron
1984,
40:
2003
<A NAME="RG10706ST-6G">6g</A>
Heck RF.
Nolley JP.
J. Org. Chem.
1972,
37:
2320
<A NAME="RG10706ST-7">7</A>
Representative Experimental Procedure.
To a flame-dried flask (under an argon atmosphere) charged with benzyl bromide (226
mg, 1.33 mmol), PdCl2(PPh3)2 (5 mol%), AsPh3 (8 mol%) and CuI (8 mol%) was added THF (5.0 mL) and the mixture warmed to 50 °C.
3,4-Bis(tributyl-stannyl)furan-2(5H)-one (450 mg, 0.66 mmol) in THF (5.0 mL) was added dropwise via syringe. After reaction
was complete the mixture was concentrated under reduced pressure. Purification via
flash chromatography (silica gel, PE-Et2O 1:1; R
f
= 0.50) gave 3,4-dibenzylfuranone as a clear colorless oil (78 mg, 45%). IR (CHCl3): 3063, 1754, 1668 cm-1. 1H NMR (250 MHz, CDCl3): δ = 3.71 (2 H, s), 3.74 (2 H, s), 4.51 (2 H, s), 6.99-7.02 (2 H, dd, J = 7.0, 2.0 Hz), 7.22-7.29 (8 H, m). 13C NMR (60 MHz, CDCl3): δ = 30.0, 34.0, 71.7, 127.0, 127.2, 127.7, 129.0, 129.1, 129.2, 129.5, 136.3, 138.5,
160.3, 175.2. MS (CI, NH3): m/z calcd for C18H16O2: 265.1231. Found [MH]+: 265.1221; m/z (%) = 219 (20), 91 (25).
For racemic and asymmetric syntheses of hinokinin, see:
<A NAME="RG10706ST-8A">8a</A>
Morimoto T.
Nagai H.
Achiwa K.
Synth. Commun.
2005,
35:
857
<A NAME="RG10706ST-8B">8b</A>
da Silva R.
de Souza GHB.
da Silva AA.
de Souza VA.
Pereira AC.
Royo VD.
Silva MLAE.
Donate PM.
Araujo ALSD.
Carvalho JCT.
Bastos JK.
Bioorg. Med. Chem. Lett.
2005,
15:
1033
<A NAME="RG10706ST-8C">8c</A>
Bennett DJ.
Pickering PL.
Simpkins NS.
Chem. Commun.
2004,
1392
<A NAME="RG10706ST-8D">8d</A>
Xia YM.
Liang QR.
Wang XL.
Cao XP.
Pan XF.
Chin. J. Chem.
2003,
21:
1540
<A NAME="RG10706ST-8E">8e</A>
Enders D.
Lausberg V.
Del Signore G.
Berner OM.
Synthesis
2002,
515
<A NAME="RG10706ST-8F">8f</A>
Brinksma J.
van der Deen H.
van Oeveren A.
Feringa BL.
J. Chem. Soc., Perkin Trans. 1
1998,
4159 ; and references therein
<A NAME="RG10706ST-9">9</A>
Data for (±)-Hinokinin.
IR (CHCl3): 1769, 1495, 1245, 1033 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.45-2.60 (3 H, m, ArCH2CH, ArCH2CH and ArCH2CHCHC=O), 2.86 (1 H, dd, J = 14.5, 7.0 Hz, ArCH2CHC=O), 2.99 (1 H, dd, J = 14.0, 5.0 Hz, ArCH2CHC=O), 3.87 (1 H, dd, J = 9.00, 7.00 Hz, OCH2), 4.14 (1 H, dd, J = 10.0, 7.00 Hz, OCH2), 5.95 (4 H, m, OCH2O), 6.46-4.48 (2 H, m, 2 × Ar,), 6.62 (2 H, m, 2 × Ar), 6.64 (2 H, m, 2 × Ar). 13C NMR (100 MHz, CDCl3): δ = 35.2, 38.8 (ArCH2), 41.7 (ArCH2CHCHC=O), 46.9 (ArCH2CHCHC=O), 71.6 (OCH2), 101.4 (OCH2O) 108.6, 108.9, 109.2, 109.8, 121.9, 122.6, 131.7, 132.0, 132.1, 146.8, 146.9, 148.3
(2 × Ar), 178.8 (C=O). MS (CI, NH3): m/z calcd for C20H19O6: 355.1181. Found [MH]+: 355.1164; m/z (%) = 135 (45).
<A NAME="RG10706ST-10A">10a</A>
Leutenegger U.
Madin A.
Pfaltz A.
Angew. Chem., Int. Ed. Engl.
1989,
28:
60
<A NAME="RG10706ST-10B">10b</A>
von Matt P.
Pfaltz A.
Tetrahedron: Asymmetry
1991,
2:
691
<A NAME="RG10706ST-10C">10c</A>
Moritani Y.
Appella DH.
Jurkauskas V.
Buchwald SL.
J. Am. Chem. Soc.
2000,
122:
6797
<A NAME="RG10706ST-10D">10d</A>
Yun J.
Buchwald SL.
Org. Lett.
2001,
3:
1129
<A NAME="RG10706ST-10E">10e</A>
Jurkauskas V.
Buchwald SL.
J. Am. Chem. Soc.
2002,
124:
2892
<A NAME="RG10706ST-10F">10f</A>
Appella DH.
Moritani Y.
Shintani R.
Ferreira EM.
Buchwald SL.
J. Am. Chem. Soc.
1999,
121:
9473