Paper
Organic & Biomolecular Chemistry
atography (4 : 1, hexanes : EtOAc), Rf = 0.19. M.p. 66–68 °C. 2-Hydroxy-1-(3-isopropoxyphenyl)-2-phenylethan-1-one (54)
δH (400 MHz, CDCl3): 4.50 (d, J 5.4, 1H), 6.20 (d, J 5.4, 1H),
7.05 (d, J 8.6, 1H), 7.36 (app. t, 2H), 7.46–7.58 (m, 4H), 7.71
Prepared according to general procedure 3 using 2-(2-bromo-
phenyl)-2-hydroxy-1-(3-isopropoxyphenyl)ethan-1-one
(41,
(dd, J 8.6, 2.0, 1H), 7.81–7.91 (m, 5H), 8.06 (d, J 2.0, 1H). δC
(100 MHz, CDCl3): 71.4, 118.0 (quart., JCF 5.8), 123.7, 123.9
(quart., JCF 276.3), 127.0, 128.9, 128.9, 129.1, 129.5 (quart., JCF
30.5), 130.3, 132.3, 132.8 (quart., JCF 1.1) 133.1, 134.1, 134.2,
138.5, 165.9, 198.6. δF (376 MHz, CDCl3): −57.95. νmax (neat)/
119 mg). After reflux for 20 min, the title product was obtained
as yellow oil (90 mg, 98%). Rf = 0.16 (9 : 1, hexanes : EtOAc). δH
(400 MHz, CDCl3): 1.25 (d, J 6.0, 3H), 1.29 (d, J 6.0, 3H),
4.45–4.53 (m, 2H), 5.89 (s, 1H), 7.00 (dd, J 8.3, 1.6, 1H),
7.23–7.32 (m, 6H, H-2), 7.40–7.47 (m, 2H). δC (100 MHz,
CDCl3): 21.7, 21.9, 70.2, 76.3, 115.2, 121.4, 122.2, 127.7, 128.5,
129.1, 129.7, 134.7, 139.1, 158.0, 198.8. νmax (neat)/cm−1: 3444,
3066, 3033, 2978, 2931, 1679, 1582, 1486, 1444, 1256, 1111,
952, 756, 698. HRMS (m/z-ESI−): found 269.1183 (C17H17O3
requires 269.1178).
cm−1
: 3381, 3062, 2976, 1674, 1596, 1530, 1419, 1317,
1262, 1160, 1114, 972, 688. HRMS (m/z-ESI+): found 422.0993
([M+ + Na]+, C22H16NO3F3Na requires 422.0980).
General procedure 3 (hydrodebromination of aromatic cross-
benzoin adducts). To a flame-dried 50 mL round-bottomed
flask equipped with a magnetic stirring bar was charged the
relevant aromatic benzoin (0.34 mmol, 1 equiv.), MeOH
(10 mL), palladium on activated charcoal (10% Pd basis)
and ammonium formate (100 mg, 1.6 mmol, 5 equiv.). The
flask was fitted with a reflux condenser, flushed with argon
and sealed with a rubber septum. The mixture was heated
under reflux and the progress of the reaction monitored via
TLC. Upon consumption of the starting material, the
reaction was allowed to cool and filtered to remove the Pd/C.
The filtrate was concentrated in vacuo before adding
CH2Cl2 (10 mL) and H2O (5 mL). The layers were separated
and the aqueous layer extracted once further with CH2Cl2
(10 mL). The combined organic extracts were dried over
MgSO4, filtered and concentrated in vacuo once more to yield
the desired product.
1-Furan-2-yl-2-hydroxy-2-phenyl-ethanone (55)
Prepared according to general procedure 3 using 2-(2-bromo-
phenyl)-1-(furan-2-yl)-2-hydroxyethan-1-one (45, 96 mg). After
refluxing for 1 hour, a further portion of ammonium formate
(100 mg, 5 equiv.) was added and refluxing continued for a
further 30 min, upon which the title product was obtained as a
tan solid in 69 mg (100%). Rf = 0.13 (9 : 1, hexanes : EtOAc).
M.p. 127 °C. δH (400 MHz, CDCl3): 4.36 (br. s, 1H), 5.75
(s, 1H), 6.48 (dd, J 3.7, 1.5, 1H), 7.19 (d, J 3.7, 1H), 7.27–7.41
(m, 5H), 7.57 (s, 1H). δC (100 MHz, CDCl3): 76.1, 112.6, 119.9,
127.7, 128.6, 128.9, 138.7, 147.3, 149.9 (q), 187.4. νmax (neat)/
cm−1: 3423, 3121, 2958, 1660, 1458, 1399, 1270, 1157, 1039,
976, 908, 811, 754, 726, 694. HRMS (m/z-ESI−): found 201.0562
(C12H9O3 requires 201.0552).
2-Hydroxy-1-(naphthalen-2-yl)-2-phenylethan-1-one (52)
Prepared according to general procedure 3 using 2-(2-bromo-
phenyl)-2-hydroxy-1-(naphthalen-2-yl)ethan-1-one (34, 116 mg).
After reflux for 1 hour, the title product was obtained as white
Conflicts of interest
There are no conflicts to declare.
solid (83 mg, 93%). Rf
= 0.16 (9 : 1, hexanes : EtOAc).
M.p. 139–141 °C. δH (400 MHz, CDCl3): 4.61 (br. s, 1H), 6.09 (s,
1H), 7.22 (obscured, 1H), 7.29 (app. t, 2H), 7.38 (d, J 7.4, 2H), Acknowledgements
7.80–7.83 (m, 2H), 7.87 (d, J 8.1, 1H), 7.94 (dd, J 8.6, 0.9, 1H),
8.43 (s, 1H). δC (100 MHz, CDCl3): 76.3, 124.2, 127.0, 127.7,
We are grateful to the Irish Research Council for financial
support.
127.8, 128.6, 128.6, 129.0, 129.1, 129.7, 130.8, 131.3, 132.2,
135.8, 139.1, 198.9. νmax (neat)/cm−1
: 3413, 3056, 2902,
1677, 1622, 1388, 1263, 1172, 1078, 1005, 794, 749, 692. HRMS
(m/z-ESI−): found 261.0905 (C18H13O2 requires 261.0916).
Notes and references
1 F. Wöhler and J. Liebig, Ann. Pharm., 1832, 3, 249.
1-(4-Fluoro-phenyl)-2-hydroxy-2-phenyl-ethanone (53)
2 P. Hoyos, J.-V. Sinisterra, F. Molinari;, A. R. Alcántara and
P. Domínguez de María, Acc. Chem. Res., 2010, 43, 288.
3 B. Rosche, V. Sandford, M. Breuer, B. Hauer and
P. L. Rogers, J. Mol. Catal. B: Enzym., 2002, 19, 109.
Prepared according to general procedure 3 using 2-(2-bromo-
phenyl)-1-(4-fluorophenyl)-2-hydroxyethan-1-one (38, 104 mg).
After reflux for 30 min, the title product was obtained as white
solid (65 mg, 83%). Rf
=
0.17 (9 : 1, hexanes : EtOAc).
4 For selected reviews, see: (a) J. L. Moore and T. Rovis, Top.
Curr. Chem., 2009, 291, 77; (b) D. Enders, J. Org. Chem.,
2008, 73, 7857; (c) T. Rovis, Chem. Lett., 2008, 37, 1;
(d) K. Zeitler, Ernst Schering Found. Symp. Proc., 2007, 2,
183; (e) D. Enders, O. Niemeier and A. Henseler, Chem.
Rev., 2007, 107, 5506; (f) N. Marion, S. Diez-Gonzalez and
S. P. Nolan, Angew. Chem., Int. Ed., 2007, 46, 2988;
(g) K. Zeitler, Angew. Chem., Int. Ed., 2005, 44, 7506;
M.p. 82–84 °C. δH (400 MHz, CDCl3): 4.49 (br. s, 1H), 5.88 (s,
1H), 7.03 (t, J 8.7, 2H), 7.26–7.35 (m, 5H), 7.92–7.95 (m, 2H). δC
(100 MHz, CDCl3): 76.2, 116.0 (d, JCF 22.0), 127.1, 127.7, 128.1
129.2, 131.9 (d, JCF 9.5), 138.8, 166.0 (d, JCF 256.8), 197.3. νmax
(neat)/cm−1: 3450, 3064, 3033, 2901, 1674, 1595, 1503, 1229,
1156, 1076, 974, 832, 757, 698. HRMS (m/z-ESI−): found
229.0654 (C14H10O2F requires 229.0665).
Org. Biomol. Chem.
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