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DOI: 10.1055/s-2002-32969
Electron Transfer Driven Transformations of Transition Metal π-Complexes: Samarium(II) Iodide Mediated Coupling of Fluoroarene-Cr(CO)3 Complexes with Ketones
Publikationsverlauf
Publikationsdatum:
25. Juli 2002 (online)
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Abstract
Fluoro-substituted η6-arene tricarbonylchromium complexes react with aliphatic ketones in the presence of SmI2 and tBuOH under C-C bond formation to give the corresponding tertiary benzylic alcohols in up to 77% yield. Chlorobenzene-Cr(CO)3 exhibit a similar reactivity. The reactions proceed through attack of a ketyl radical to the complexed arene followed by single electron reduction of the 17 VE intermediate. The overall reaction parallels a nucleophilic aromatic substitution of fluoride (SNAr) and preferentially occurs in a meta-tele fashion.
Key words
arene-chromium complexes - nucleophilic aromatic substitution - radical reactions - electron transfer - samarium(II) iodide
- Selected overviews:
-
1a
Schmalz H.-G.Siegel S. In Transition Metals for Organic Synthesis Vol. 1:Beller M.Bolm C. Wiley-VCH; Weinheim: 1998. p.550 -
1b
Hegedus LS. Transition Metals in the Synthesis of Complex Organic Molecules 2nd ed.: University Science Books; Sausalito, CA: 1999. Chap. 10. -
1c
Pape AR.Kaliappan KP.Kündig EP. Chem. Rev. 2000, 100: 2917 -
1d
Kamikawa K.Uemura M. Synlett 2000, 938 -
1e
Kamikawa K.Watanabe T.Uemura M. J. Synth. Org. Chem., Jpn. 2001, 59: 1078 -
1f
Carpentier J.-F.Petit F.Mortreux A.Dufand V.Basset J.-M.Thivolle-Cazat J. J. Mol. Catal. 1993, 81: 1 -
2a
Schmalz H.-G.Siegel S.Bats JW. Angew. Chem., Int. Ed. Engl. 1995, 34: 2383 ; Angew. Chem. 1995, 107, 2597 -
2b
Schmalz H.-G.Siegel S.Schwarz A. Tetra-hedron Lett. 1996, 37: 2947 -
2c
Hoffmann O.Schmalz H.-G. Synlett 1998, 1426 -
2d
Schwarz O.Brun R.Bats JW.Schmalz H.-G. Tetrahedron Lett. 2002, 43: 1009 -
3a
Merlic CA.Walsh JC. J. Org. Chem. 2001, 66: 2265 -
3b
Taniguchi N.Uemura M. Synlett 1997, 51 -
3c
Taniguchi N.Hata T.Uemura M. Angew. Chem. Int. Ed. 1999, 38: 1232 -
3d
Taniguchi N.Uemura M. Tetrahedron 1998, 54: 12775 -
3e
Monovich LG.Le Huerou Y.Ronn M.Molander GA. J. Am. Chem. Soc. 2000, 122: 52 -
4a
Schmalz H.-G.de Koning CB.Bernicke D.Siegel S.Pfletschinger A. Angew. Chem. Int. Ed. 1999, 38: 1620 -
4b
Schmalz H.-G.Siegel S.Bernicke D. Tetrahedron Lett. 1998, 39: 6683 -
5a
Kagan HB. New J. Chem. 1990, 14: 453 -
5b
Molander GA. Chem. Rev. 1992, 92: 29 -
5c
Inanaga J. Heteroat. Chem. 1990, 3: 75 - 6
Yeh M.-CP.Wang F.-C.Tu J.-J.Chang S.-C.Chou C.-C.Liao J.-W. Organometallics 1998, 17: 5656 - 7
Siegel S. PhD Thesis TU Berlin; Berlin: 1998. -
9a
Semmelhack MF. In Comprehensive Organometallic Chemistry II Vol. 12:Abel EW.Stone FGA.Wilkinson G. Pergamon Press; New York: 1995. p.979 -
9b
Semmelhack MF. In Comprehensive Organometallic Chemistry II Vol. 12:Abel EW.Stone FGA.Wilkinson G. Pergamon Press; New York: 1995. p.1039 -
9c
Rose-Munch F.Gagliardini V.Renard C.Rose E. Coord. Chem. Rev. 1998, 178-180: 249 -
9d
Rose-Munch F.Rose E. Curr. Org. Chem. 1999, 3: 445 - 10
Mahaffy CA.Pauson PL. Inorg. Synth. 1990, 28: 136 - 11
Inanaga J.Ishikawa M.Yamaguchi M. Chem. Lett. 1987, 1485 - 12
Batey RA.Motherwell WB. Tetrahedron Lett. 1991, 32: 6649 - 15
Rose-Munch F.Rose E.Semra A.Mignon L.Garcia-Oricain J.Knobler C. J. Organomet. Chem. 1989, 363: 297 - 16
Merlic CA.Miller MM.Hietbrink BN.Houk KN. J. Am. Chem. Soc. 2001, 123: 4904 - 17
Lin HC.Zhang HJ.Yang L.Li CZ. Org. Lett. 2002, 4: 823
References
Only one enantiomer of racemic compounds is depicted.
13Typical Experimental Procedure: A
flame dried Schlenk flask was charged with 15 mL of a 0.1 M solution
of SmI2 in THF and HMPA (1.5 mL) under argon. After cooling
to 0 °C, a solution of the fluorobenzene-Cr(CO)3 complex(11) (116 mg, 0.5 mmol), tBuOH
(145 µL, 1.5 mmol) and acetone (45 µL, 0.6 mmol)
in THF (3 mL) was added dropwise via cannula over a period of 5
min. The resulting mixture was stirred at 0 °C for 90 min
and for 60 min at r.t. before it was quenched with saturated aqueous
NaHCO3 (5 mL). After stirring for another 5 min, the
reaction mixture was filtered through a short pad of Celite® and
washed with MTBE. The organic layer was washed with saturated NaHCO3 solution, brine,
dried over Na2SO4 and evaporated. The residue
was purified by chromatography (20g of SiO2, CyH-EtOAc = 3:1)
to give 105 mg (77%) of complex 12 as
yellow crystalline compound. Mp 73 °C. 1H
NMR (270 MHz, CDCl3): 1.56 (s, 6 H); 5.31 (t, 2 H, J = 6.5 Hz); 5.42 (t, 1 H, J = 6.5 Hz); 5.64 (d, 2 H, J = 6.5 Hz). 13C
NMR (67.7 MHz, CDCl3): 31.3; 70.8; 91.3; 91.5; 93.4;
121.3; 232.53. FT-IR (ATR): 3576; 3483; 3092; 2985; 2932; 1948;
1892; 1854; 1457; 1415; 1366; 1168; 1154; 1096; 1054; 966; 861;
821; 662 cm-1. HRMS: for C12H12CrO4 calcd.:
272.0141; found: 272.0144.
Compound 13:
Mp 98 °C. 1H NMR (400 MHz, CDCl3): 1.58-1.70
(m, 5 H); 1.70-1.86 (m, 5 H); 5.26 (t, 2 H, J = 6.5 Hz);
5.44 (t, 1 H, J = 6.5 Hz); 5.68
(d, 2 H, J = 6.5 Hz). 13C NMR
(100 MHz, CDCl3): 21.8; 25.2; 38.9; 71.4; 90.8; 92.1; 94.0;
121.8; 233.4. FT-IR (ATR): 3582; 3093; 2936; 2859; 1959; 1869; 1449;
1411; 1350; 1309; 1261; 1203; 1153; 1123; 1034; 1022; 978; 849;
814; 688 cm-1. HRMS: for C15H16CrO4 calcd.:
312.0454; found: 312.0454.
Compound 14:
Mp 71 °C. 1H NMR (270 MHz, CDCl3): 1.77-2.09
(m, 8 H); 5.31-5.43 (m, 3 H); 5.64 (dd, 2 H, J
1 = 6.5
Hz, J
2 = 2 Hz). 13C
NMR (67.7 MHz, CDCl3): 24.3; 42.4; 81.6; 91.4; 92.1;
92.8; 118.7; 233.4. FT-IR (ATR): 3582; 3443; 3088; 2958; 2875; 1957;
1865; 1458; 1412; 1327; 1295; 1233; 1189; 1152; 1009; 949; 903;
882; 817; 661
cm-1. HRMS:
for C14H14CrO4 calcd.: 298.0297;
found: 298.0293.
Compound rac-15: Mp 119 °C. 1H
NMR (400 MHz, CDCl3): 1.64 (s, 3 H); 1.97 (t, 2 H, J = 5.5 Hz); 3.79 (dtt, 1 H, J
1 = 10 Hz, J
2 = 5.5 Hz, J
3 = 5 Hz); 3.90
(dtt, 1 H, J
1 = 10 Hz, J
2 = 5.5 Hz, J
3 = 5 Hz); 5.25
(t, 1 H, J = 6 Hz); 5.29 (t,
1 H, J = 6.5 Hz); 5.43 (t, 1
H, J = 6 Hz); 5.45 (d, 1 H, J = 6 Hz); 5.80 (d, 1 H, J = 6.5 Hz). 13C
NMR (100 MHz, CDCl3): 29.1; 44.9; 59.7; 70.6; 90.5; 90.6;
91.7; 92.0; 93.7; 120.0; 233.1. FT-IR (ATR): 3363; 2978; 2893; 1958;
1870; 1457; 1413; 1378; 1298; 1153; 1083; 1054; 1014; 965; 881;
816; 662
cm-1. HRMS: for C13H14CrO5 calcd.:
302.0246; found: 302.0247.
Compound rac-16: Mp 114 °C. 1H
NMR (400 MHz, CDCl3): 1.60 (s, 3 H); 2.72 (d, 1 H, J = 16 Hz); 2.79 (d, 1 H, J = 16 Hz); 3.74 (s, 3 H); 5.22
(t, 2 H, J = 6.5 Hz); 5.46 (t,
1 H, J = 6.5 Hz); 5.62 (d, 1
H, J = 6.5 Hz); 5.68 (d, 1 H, J = 6.5 Hz). 13C
NMR (100 MHz, CDCl3): 30.0; 46.6; 52.1; 70.9; 89.6; 89.7;
91.8; 92.1; 94.0; 117.9; 172.0; 232.7. FT-IR (ATR): 3482; 3092;
2954; 2927; 1958; 1866; 1854; 1713; 1457; 1438; 1412; 1374; 1342;
1207; 1180; 1095; 1069; 1049; 1009; 958; 857; 816; 660 cm-1.
HRMS: for C14H14CrO6 calcd.: 330.0195;
found: 330.0195.
Preliminary attempts to employ aldehydes instead of ketones under similar conditions were not successful. In these cases, only the reduced aldehydes (alcohols) and some pinacol-type coupling products were formed, and the unchanged fluorobenzene-Cr(CO)3 derivatives could be reisolated.