Pd-Catalyzed Cross-Coupling of Chloroarene-Cr(CO)₃ Complexes with Stabilized Organoindium (III) Reagents Under Remarkably Mild Conditions

Abstract

The palladium catalyzed cross-methylation of intramolecularly stabilized dimethylindium (III) compounds (3 and 4) with different chloroarene-Cr(CO)₃ complexes have been studied. Under mild conditions (40 °C in THF, 3 h) high yields (up to 96%) of the coupling products were obtained in the presence of 1-10 mol% of PdCl₂(PPh₃)₂. With MeMgCl almost no conversion was observed under the same conditions.

arene-chromium complexes - indium(III) reagents - palladium - catalysis - cross-coupling - methylation

References

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., Chap. 10:  University Science Books; Sausalito, CA: 1999. 

1c Bolm C. Muniz K. Chem. Soc. Rev.  1999,  28:  51 

1d Pape AR. Kaliappan KP. Kündig EP. Chem. Rev.  2000,  100:  2917 

1e Kamikawa K. Uemura M. Synlett  2000,  938 

2a Metal-Catalyzed Cross-Coupling Reactions   Diederich F. Stang PJ. Wiley-VCH; Weinheim: 1997. 

2b Tsuji J. Palladium Reagents and Catalysts   Wiley; Chichester: 1996. 

3 For reviews on C_Ar-Cl bond activation trough Cr(CO)₃ complexation, see: Carpentier J.-F. Petit F. Mortreux A. Dufand V. Basset J.-M. Thivolle-Cazat J. J. Mol. Catal.  1993,  81:  1 

For some recent works, see:

4a Müller TJJ. Ansorge M. Aktah D. Angew. Chem.  2000,  112:  1323 

4b Bräse S. Tetrahedron Lett.  1999,  40:  6757 

4c Kündig EP. Ratni H. Crousse B. Bernardinelli G. J. Org. Chem.  2001,  66:  1852 

4d Kamikawa K. Tachibana A. Sugimoto S. Uemura M. Org. Lett.  2001,  3:  2033 

4e Gotov B. Schmalz H.-G. Org. Lett.  2001,  2:  1753 

4f Wilhelm R. Widdowson DA. Perkin Trans. 1  2000,  3808 

4g Prim D. Tranchier J.-P. Chavignon R. Rose-Munch F. Rose E. Organometallics  2001,  20:  1279 

For recent work from this laboratory, see:

5a Dehmel F. Schmalz H.-G. Org. Lett.  2001,  3:  3579 

5b Hörstermann DP. Schmalz H.-G. Kociok-Köhn G. Tetrahedron  1999,  55:  6905 

5c Schmalz H.-G. de Koning CB. Bernicke D. Siegel S. Pfletschinger A. Angew. Chem. Int. Ed. Engl.  1999,  38:  1620 ; Angew. Chem. 1999, 111, 1721

5d Hoffmann O. Schmalz H.-G. Synlett  1998,  1426 

6a Gelman D. Schumann H. Blum J. Tetrahedron Lett.  2000,  41:  7555 

6b Blum J. Katz JA. Jaber N. Michman M. Schumann H. Schutte S. Kaufmann J. Wassermann BC. J. Mol. Catal. A.  2001,  165:  97 

7a

For the synthesis and full characterization of reagents 3 and 4, see: Schumann, H.; Kaufmann, J.; Wassermann, B. C.; Girgsdies, F.; Jaber, N.; Blum, J. Z. Anorg. Allg. Chem., in press. Compound 3 had been previously descibed by:

7b Maeda T. Okawara RJ. Organomet. Chem.  1972,  39:  87 

8 Perez I. Sestelo JP. Sarandeses LA. Org. Lett.  1999,  1:  1267 

9 Perez I. Sestelo JP. Sarandeses LA. J. Am. Chem. Soc.  2001,  123:  4155 

10 Legros J.-Y. Primault G. Fiaud J.-C. Tetrahedron  2001,  57:  2507 

11 Takami K. Yorimitsu H. Shinokubo H. Matsubara S. Oshima K. Org. Lett.  2001,  3:  1997 

12 Lee PH. Sung S.-Y. Lee K. Org. Lett.  2001,  3:  3201 

13

Typical Experimental Procedure: The indium reagent 4 [0.5 mmol of In(III), 123 mg], PdCl₂(PPh₃)₂ (1 mol%, 3.6 mg) and 1 (0.5 mmol, 124 mg) were placed in flame dried Schlenk-flask equipped with a reflux condenser, evacuated and flushed with argon. Deoxygenated anhydrous THF (3 mL) was added via syringe and the reaction mixture was placed in an oil bath pre-heated to 40 C. After stirring at 40 °C for 3 h under an argon atmosphere, the reaction mixture was cooled to ambient temperature, diluted with MTBE (5 mL), filtered trough a short pad of silica, washed with MTBE and concentrated under reduced pressure. The residue was purified by chromatography on silica (10 g) with cyclohexane-ethyl acetate = 10:1 to give 108 mg (95%) of the product 5 as a yellow crystalline solid with >97% purity according to HPLC analysis. Mp 81-82 °C (ref. [16a] 80-81 °C); ¹H NMR (250 MHz, CDCl₃) δ = 5.36-5.41 (m, 2 H), 5.10-5.14 (m, 3 H), 2.17 (s, 3 H); ¹³C NMR (62.5 MHz, CDCl₃) δ = 233.2, 109.6, 94.4, 92.8, 89.6, 20.8; FT-IR(neat): 1443, 1857, 1950 cm^-1.

14

Compound rac-7: Mp 83-84 °C (ref. [16b] 84-85 °C); ¹H NMR (250 MHz, CDCl₃) δ = 6.15 (dd, 1 H), 5.55 (dt, 1 H), 5.12 (dt, 1 H), 5.03 (dd, 1 H), 3.85 (s, 3 H), 2.49 (s, 3 H); ¹³C NMR (62.5 MHz , CDCl₃) δ = 231.2, 166.3, 111.9, 95.4, 92.2, 90.1, 87.5, 52.6, 21.2; FT-IR(neat): 1433, 1719, 1881, 1963 cm^-1.

15

Compound rac-9: Mp 94-96 °C (ref. [16b] not given); ¹H NMR (250 MHz, CDCl₃) δ = 5.56 (dd, 1 H), 5.34 (dd, 1 H), 5.24 (dt, 1 H), 5.10 (dt, 1 H), 2.30 (s, 3 H); ¹³C NMR (62.5 MHz, CDCl₃) δ = 232.0, 111.7, 107.9, 93.7, 93.1, 90.8, 90.4, 19.4; FT-IR(neat): 1445, 1865, 1958 cm^-1.

16a Fischer EO. Öfele K. Essler H. Fröhlich W. Mortensen P. Semmlinger W. Chem. Ber.  1958,  91:  2763 

16b Slawish A. In Gmelins Handbuch der Anorganischen Chemie, Chrom-Organische Verbindungen   Band 3:  Slawisch A. Verlag Chemie; Weinheim: 1972.  p.224 

17 Schumann H. Kaufmann J. Dechert S. Schmalz H.-G. Velder J. Tetrahedron Lett.  2001,  42:  5405