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Synlett 2015; 26(01): 87-90
DOI: 10.1055/s-0034-1378935
letter
© Georg Thieme Verlag Stuttgart · New York

Reduction of Pseudo-geminal Bis(ethynyl)-Substituted [2.2]Paracyclophanes

Laura G. Sarbu
a   Department of Organic Chemistry, ‘Al. I. Cuza’ University of Iasi, 11 Carol I, 700506 Iasi, Romania   Fax: +40(232)201313   Email: lbirsa@uaic.ro
b   Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
,
Henning Hopf
b   Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
,
Jörg Grunenberg
b   Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
,
Lucian M. Birsa*
a   Department of Organic Chemistry, ‘Al. I. Cuza’ University of Iasi, 11 Carol I, 700506 Iasi, Romania   Fax: +40(232)201313   Email: lbirsa@uaic.ro
b   Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
› Author Affiliations
Further Information

Publication History

Received: 01 August 2014

Accepted after revision: 20 October 2014

Publication Date:
18 November 2014 (online)

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Abstract

The reduction of pseudo-geminal bis(ethynyl)-substituted [2.2]paracyclophanes provides compounds with new bridges. The type of bridging is substituent dependent. The (trimethylsilyl)ethynyl moiety induces the formation of a bridge with two semicyclic double bonds; less bulky substituents, like propynyl and phenylethynyl, lead to bridges with endo double bonds.

Key words

acetylenes - reduction - dienes - lithium - paracyclophanes
 

  • References and Notes

  • 1 Brown CJ, Farthing AC. Nature (London, U.K.) 1949; 164: 915
    PubMed
  • 2 Cram DJ, Steinberg H. J. Am. Chem. Soc. 1951; 73: 5691
    Crossref
  • 3 Vögtle F, Neumann P. Synthesis 1973; 85
    Article in Thieme Connect
  • 4 Staab HA, Knaus GH, Henke H.-E, Krieger C. Chem. Ber. 1983; 116: 2785
    Crossref
  • 5 Boekelheide V. Top. Curr. Chem. 1983; 113: 87
  • 6 Hopf H, Marquard C In Strain and its Implications in Organic Chemistry . de Meijere A, Blechert S. Kluwer; Dordrecht: 1983: 297
    Google Scholar
  • 8 Hopf H, Psiorz M. Chem. Ber. 1986; 119: 1836
    Crossref
  • 9 Greiving H, Hopf H, Jones PG, Bubenitschek P, Desvergne J.-P, Bouas-Laurent H. Eur. J. Org. Chem. 2005; 558
  • 10 Hopf H, Greiving H, Beck C, Dix I, Jones PG, Desvergne J.-P, Bouas-Laurent H. Eur. J. Org. Chem. 2005; 567
  • 11 For a review, see: Hopf H. Angew. Chem. Int. Ed. 2003; 42: 2822 ; Angew. Chem. 2003, 115, 2928
    CrossrefPubMed
  • 12 Bondarenko L, Dix I, Hinrich H, Hopf H. Synthesis 2004; 2751
    Article in Thieme Connect
  • 13 For a review, see: Hafner K. Nachr. Chem. Tech. Lab. 1980; 28: 222
  • 14 For a review on pentalene synthetic methods, see: Hopf H. Angew. Chem. 2013; 125: 12446 ; Angew. Chem. Int. Ed. 2013, 52, 12224
    Crossref
  • 15 Saito M, Nakamura M, Tajima T, Yoshioka M. Angew. Chem. Int. Ed. 2007; 46: 1504 ; Angew. Chem. 2007, 119, 1374
    Crossref
  • 16 Typical ProcedureTo a solution of 4,13-bis(trimethylsilyl)[2.2]paracyclophane (3, 167 mg, 0.4 mmol) in dry THF (10 mL) was added powdered lithium (28 mg, 4 mmol). The reaction mixture was stirred at r.t. until the starting material had been consumed (12 h, TLC monitoring). Filtration through Celite followed by evaporation under vacuo gave the crude product that was purified by column chromatography to provide compound 4 as a colorless solid (40 mg, 25%); Rf = 0.59 (CH2Cl2–pentane, 1:5); mp 125–126 °C. IR (ATR): 2981, 1545, 1311, 914, 857, 829 cm–1. 1H NMR (400 MHz, CDCl3, TMS): δ = 0.11 (s, 18 H, 6 CH3), 2.65 (m, 2 H, CH2), 3.05 (m, 6 H, 3 CH2), 6.19 (d, 4 J = 2.1 Hz, 2 H, 2 CHar), 6.34 (d, 3 J = 8.1 Hz, 2 H, 2 CHar), 6.44 (dd, 3 J = 8.1 Hz, 4 J = 2.1 Hz, 2 H, 2CHar) ppm. 13C NMR (100 MHz, CDCl3, TMS): δ = 0.2, 32.7, 36.2, 120.2, 130.4, 132.5, 139.1, 139.4, 139.9, 143.6, 158.7 ppm. MS (EI): m/z (%) = 402 (65) [M+], 73 (100).
  • 17 Spectral Data of 6aColorless solid, 15 mg, 10%; Rf = 0.4 (CH2Cl2–pentane, 1:10); mp 142–143 °C. IR (ATR): 2954, 1575, 1451, 1333, 1211, 870, 771 cm–1. 1H NMR (400 MHz, CDCl3, TMS): δ = 2.05 (s, 6 H, 2 CH3), 2.7 and 3.7 (ABq, 2 J = 10.4 Hz, 4 H, 2 CH2), 2.90 (m, 2 H, CH2), 2.98 (s, 4 H, 2 CH2), 3.58 (m, 2 H, CH2), 6.20 (d, 4 J = 2.2 Hz, 2 H, 2 CHar), 6.27 (dd, 3 J = 8.0 Hz, 4 J = 2.2 Hz, 2 H, 2 CHar), 6.35 (d, 3 J = 8.0 Hz, 2 H, 2 CHar) ppm. 13C NMR (100 MHz, CDCl3, TMS): δ = 23.2, 32.0, 35.2, 37.4, 130.5, 130.8, 132.5, 134.0, 136.5, 139.5, 140.3 ppm. MS (EI): m/z (%) = 288 (20) [M+], 169 (100).
  • 18 Spectral Data of 7aPale yellow solid, 16 mg, 11%; Rf = 0.64 (CH2Cl2–pentane, 1:10); mp 138–139 °C. IR (ATR): 2934, 1551, 1420, 1341, 1201, 845, 742 cm–1. 1H NMR (400 MHz, CDCl3, TMS): δ = 2.13 (s, 6 H, 2 CH3), 2.30 (s, 6 H, 2 CH3), 3.06 (m, 4 H, 2 CH2), 6.12 (s, 2 H, 2 CH), 7.05 (m, 6 H, 6 CHar) ppm. 13C NMR (100 MHz, CDCl3, TMS): δ = 19.4, 19.6, 38.2, 126.5, 126.9, 128.6, 130.4, 135.8, 136.5, 138.4, 141.2 ppm. MS (EI): m/z (%) = 288 (23) [M+], 171 (100).
  • 19 Spectral Data of 8Pale yellow solid, 17 mg, 10%; Rf = 0.56 (CH2Cl2–pentane, 1:10); mp 133–134 °C. IR (ATR): 2917, 1547, 1412, 1301, 1218, 931, 752 cm–1. 1H NMR (400 MHz, CDCl3, TMS): δ = 1.72 (s, 6 H, 2 CH3), 2.32 (s, 6 H, 2 CH3), 2.37 (s, 6 H, 2 CH3), 2.61 (s, 4 H, 2 CH2), 3.38 (s, 4 H, 2 CH2), 6.35 (s, 2 H, 2 CH), 6.87 (dd, 3 J = 7.7 Hz, 4 J = 1.8 Hz, 2 H, 2 CHar), 6.98 (d, 3 J = 7.7 Hz, 2 H, 2 CHar), 7.05 (d, 4 J = 1.8 Hz, 2 H, 2 CHar) ppm. 13C NMR (100 MHz, CDCl3, TMS): δ = 19.4, 20.1, 20.9, 37.1, 38.0, 126.1, 127.0, 128.8, 129.8, 132.7, 133.5, 136.2, 138.0 ppm. MS (EI): m/z (%) = 346 (2) [M+], 171 (100).
  • 20 Marshall JL, Folsom TK. Tetrahedron Lett. 1971; 757