Download PDF
Synlett 2009(2): 310-314  
DOI: 10.1055/s-0028-1087667
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Dicationic Palladium(II)-Spiro bis(isoxazoline) Complex for Highly Enantioselective Isotactic Copolymerization of CO with Styrene Derivatives

Gan B. Bajracharya, Priti S. Koranne, Tetsuya Tsujihara, Shinobu Takizawa, Kiyotaka Onitsuka, Hiroaki Sasai*
The Institute of Scientific and Industrial Research (ISIR), Osaka University, Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan
Fax: +81(6)68798469; e-Mail: sasai@sanken.osaka-u.ac.jp;
Further Information

Publication History

Received 27 September 2008
Publication Date:
15 January 2009 (online)

    Permissions and Reprints All articles of this category

Abstract

The enantioseletive alternating copolymerization of CO with styrene derivatives catalyzed by a dicationic palladium(II) complex of tetra isopropyl-substituted spiro bis(isoxazoline) (i-Pr-SPRIX) is developed. This polymerization proceeded efficiently to produce isotactic polyketones with high molecular weights and high molar optical rotation values.

Key words

copolymerization - isotactic polyketones - spiro bis(isoxazoline) ligands (SPRIX) - dicationic palladium(II) complex

    References and Notes

  • 1a Okamoto Y. Yashima E. Yamamoto C. In Materials-Chirality   Green AM. Nolte RJM. Meijer EW. Wiley-Interscience; New York: 2003.  p.157 
  • 1b Consiglio G. Milani B. In Catalytic Synthesis of Carbon Monoxide/Alkenes Copolymers and Cooligomers   Sen A. Kluwer Academic; Dordrecht: 2003.  p.189 
  • 1c Nozaki K. In Catalytic Synthesis of Carbon Monoxide/Alkenes Copolymers and Cooligomers   Sen A. Kluwer Academic; Dordrecht: 2003.  p.217 
  • 2a Brookhart M. Wagner MI. Balavoine GGA. Haddou HA. J. Am. Chem. Soc.  1994,  116:  3641 
    Search in Google Scholar
  • 2b Brookhart M. Wagner MI. J. Am. Chem. Soc.  1996,  118:  7219 
    Search in Google Scholar
  • 3a Bartolini S. Carfagna C. Musco A. Macromol. Rapid Commun.  1995,  16:  9 
    Search in Google Scholar
  • 3b Scarel A. Durand J. Franchi D. Zangrando E. Mestroni G. Carfagna C. Mosca L. Seraglia R. Consiglio G. Milani B. Chem. Eur. J.  2005,  11:  6014 
    Search in Google Scholar
  • 4 Schätz A. Scarel A. Zangrando E. Mosca L. Carfagna C. Gissibl A. Milani B. Reiser O. Organometallics  2006,  25:  4065 
    CrossrefSearch in Google Scholar
  • 5a Nozaki K. Sato N. Takaya H. J. Am. Chem. Soc.  1995,  117:  9911 
    Search in Google Scholar
  • 5b Nozaki K. Sato N. Tonomura Y. Yasutomi M. Takaya H. Hiyama T. Matsubara T. Koga N. J. Am. Chem. Soc.  1997,  119:  12779 
    Search in Google Scholar
  • 5c Nozaki K. Kawashima Y. Nakamoto K. Hiyama T. Polym. J.  1999,  31:  1057 
    Search in Google Scholar
  • 5d Nozaki K. Komaki H. Kawashima Y. Hiyama T. Matsubara T. J. Am. Chem. Soc.  2001,  123:  534 
    Search in Google Scholar
  • 6a Sperrle M. Aeby A. Consiglio G. Pfaltz A. Helv. Chim. Acta  1996,  79:  1387 
    Search in Google Scholar
  • 6b Aeby A. Bangerter F. Consiglio G. Helv. Chim. Acta  1998,  81:  764 
    Search in Google Scholar
  • 6c Aeby A. Gsponer A. Consiglio G. J. Am. Chem. Soc.  1998,  120:  11000 
    Search in Google Scholar
  • 6d Aeby A. Consiglio G. Inorg. Chim. Acta  1999,  296:  45 
    Search in Google Scholar
  • 6e Gsponer A. Schmid TM. Consiglio G. Helv. Chim. Acta  2001,  84:  2986 
    Search in Google Scholar
  • For reviews, see:
  • 7a Sen A. Acc. Chem. Res.  1993,  26:  303 
    Search in Google Scholar
  • 7b Okamoto Y. Nakano T. Chem. Rev.  1994,  94:  349 
    Search in Google Scholar
  • 7c Drent E. Budzelaar PHM. Chem. Rev.  1996,  96:  663 
    Search in Google Scholar
  • 7d Bianchini C. Meli A. Coord. Chem. Rev.  2002,  225:  35 
    Search in Google Scholar
  • 7e Nakano K. Kosaka N. Hiyama T. Nozaki K. Dalton Trans.  2003,  4039 
  • 7f Nozaki K. J. Polym. Sci., Part A: Polym. Chem.  2004,  42:  215 
    Search in Google Scholar
  • 7g Durand J. Milani B. Coord. Chem. Rev.  2006,  250:  542 
    Search in Google Scholar
  • 8 Binotti B. Carfagna C. Gatti G. Martini D. Mosca L. Pettinari C. Organometallics  2003,  22:  1115 ; and references cited therein
    CrossrefSearch in Google Scholar
  • 9a Arai MA. Arai T. Sasai H. Org. Lett.  1999,  1:  1795 
    Search in Google Scholar
  • 9b Arai MA. Kuraishi M. Arai T. Sasai H. J. Am. Chem. Soc.  2001,  123:  2907 
    Search in Google Scholar
  • 9c Shinohara T. Arai MA. Wakita K. Arai T. Sasai H. Tetrahedron Lett.  2003,  44:  711 
    Search in Google Scholar
  • 9d Muthiah C. Arai MA. Shinohara T. Arai T. Takizawa S. Sasai H. Tetrehedron Lett.  2003,  44:  5201 
    Search in Google Scholar
  • 11 Because of the low coordination ability of i-Pr-SPRIX(1), it could not replace COD as ligand in [Pd(cod)(Me)(Cl)], thus an alternative route was developed to synthesize complex 3. For a general literature procedure to synthesize a methyl-Pd complex, see: Rülke RE. Ernsting JM. Spek AL. Elsevier CJ. van Leeuwen PWNM. Vrieze K. Inorg. Chem.  1993,  32:  5769 
    CrossrefSearch in Google Scholar
  • For dicationic Pd(II) complexes used in CO/styrene copolymerization, see:
  • 12a Jiang Z. Adams SE. Sen A. Macromolecules  1994,  27:  2694 
    Search in Google Scholar
  • 12b Aeby A. Gsponer A. Sperrle M. Consiglio G. J. Organomet. Chem.  2000,  603:  122 
    Search in Google Scholar
  • 12c Milani B. Scarel A. Durand J. Mestroni G. Seraglia R. Carfagna C. Binotti B. Macromolecules  2003,  36:  6295 
    Search in Google Scholar
  • 12d Bergman SD. Goldberg I. Carfagna C. Mosca L. Kol M. Milani B. Organometallics  2006,  25:  6014 ; and references cited therein
    Search in Google Scholar
  • 15 A similar effect of p-benzoquinone has been reported. When the amount of the oxidant is increased, the selectivity of the copolymerization is shifted towards formation of copolymer with a low M w. See: Barsacchi M. Consiglio G. Medici L. Petrucci G. Suter UW. Angew. Chem., Int. Ed. Engl.  1991,  30:  989 
    CrossrefSearch in Google Scholar
  • 16a Ford PC. Acc. Chem. Res.  1981,  14:  31 
    Search in Google Scholar
  • 16b Jiang Z. Dahlen GM. Houseknecht K. Sen A. Macromolecules  1992,  25:  2999 
    Search in Google Scholar
  • 18 The use of hydroquinone assists in polymer termination, see: Pisano C. Nefkens SCA. Consiglio G. Organometallics  1992,  11:  1975 
    CrossrefSearch in Google Scholar
10

See the supporting information for this article.

13

Crystal Data
C46H76B2F8N4O4Pd, monoclinic; space group C2/c (#15); a = 21.325 (9) Å, b = 15.977 (4) Å, c = 61.30 (3) Å; β = 96.74 (3)˚; V = 20742 (14) ų; Z = 16; R = 0.123, R w = 0.142; D c = 1.330 g/cm³. The unit cell contained two crystallographically independent molecules with similar structures.

14

The Pd(II)-promoted copolymerization is reported to be suppressed in the absence of an oxidant, see ref. 7c and 4.

17

A small amount of water in the reaction media might assist in the conversion of 5 to 6. The reactions in CH2Cl2/D2O (500:1, 100:1) were found to yield shorter M n of polymer than that of M n when using anhyd CH2Cl2. However, the ²H NMR spectrum of copolymer exhibited no deuterium-labeled initiating group.