Cross-Coupling Reactions with Acetylenic Dithiafulvenes

Abstract

The scope of acetylenic dithiafulvenes in palladium-catalyzed cross-coupling reactions is reported. From such reactions we have obtained a selection of new extended tetrathiafulvalenes (TTFs), based on p-diethynylbenzene, tri-, and tetraethynylethene cores.

Key words

alkynes - conjugation - cross-coupling - enynes - heterocycles

References

• 1a Nielsen MB. Moonen NNP. Boudon C. Gisselbrecht J.-P. Seiler P. Gross M. Diederich F. Chem. Commun.  2001,  1848 
• 1b Nielsen MB. Utesch NF. Moonen NNP. Boudon C. Gisselbrecht J.-P. Concilio S. Piotto SP. Seiler P. Günter P. Gross M. Diederich F. Chem.-Eur. J.  2002,  8:  3601 
• 1c Nielsen MB. Synlett  2003,  1423 
• 1d Kumagai T. Tomura M. Nishida J.-i. Yamashita Y. Tetrahedron Lett.  2003,  6845 
• 1e Nielsen MB. Gisselbrecht J.-P. Thorup N. Piotto SP. Boudon C. Gross M. Tetrahedron Lett.  2003,  44:  6721 
• 1f Qvortrup K. Jakobsen MT. Gisselbrecht J.-P. Boudon C. Jensen F. Nielsen SB. Nielsen MB. J. Mater. Chem.  2004,  14:  1768 
• 2 Hay AS. J. Org. Chem.  1962,  27:  3320 
• 3a Williams JM. Ferraro JR. Thorn RJ. Carlson KD. Geiser U. Wang HH. Kini AM. Whangbo M.-H. Organic Superconductors (Including Fullerenes): Synthesis, Structure, Properties, and Theory   Prentice Hall; Englewood Cliffs / New Jersey: 1992. 
• 3b Roncali J. J. Mater. Chem.  1997,  7:  2307 
• 3c Nielsen MB. Lomholt C. Becher J. Chem. Soc. Rev.  2000,  29:  153 
• 4 For a recent account on acetylenic modules for acetylenic scaffolding, see: Nielsen MB. Diederich F. Synlett  2002,  544 
• 5 Siemsen P. Livingston RC. Diederich F. Angew. Chem. Int. Ed.  2000,  39:  2632 
• 6a Sonogashira K. Tohda Y. Hagihara N. Tetrahedron Lett.  1975,  4467 
• 6b Takahashi S. Kuroyama Y. Sonogashira K. Hagihara N. Synthesis  1980,  627 
• 6c Sonogashira K. In Metal-Catalyzed Cross-Coupling Reactions   Diederich F. Stang PJ. Wiley-VCH; Weinheim: 1998.  p.203-229  
• 10 Tykwinski RR. Schreiber M. Carlón RP. Diederich F. Gramlich V. Helv. Chim. Acta  1996,  79:  2249 
• 11 For a recent review on electron-rich phosphines in organic synthesis, see: Valentine DH. Hillhouse JH. Synthesis  2003,  2437 
• 12 Hundertmark T. Littke AF. Buchwald SL. Fu GC. Org. Lett.  2000,  2:  1729 
• 14 The aldehyde 10 was prepared according to a literature procedure: Tretyakov EV. Tkachev AV. Rybalova TV. Gatilov YV. Knight DW. Vasilevsky SF. Tetrahedron  2000,  56:  10075 
• 15 Corey EJ. Fuchs PL. Tetrahedron Lett.  1972,  3769 

7

Gaussian 03, Revision B.03, Frisch, M. J. et al., Gaussian Inc., Pittsburg PA, 2003.

8

The acetylene and acetylide structures were geometry optimized at the semiempirical PM3 level. Frequencies were calculated to verify that the calculated structures are local minima on the potential energy surface and to correct for zero-point kinetic energies. Single-point energy calculations were performed on the optimized structures at the B3LYP/6-311++G(2d,p) level.

9

All new compounds were fully characterized by ¹H NMR and ¹³C NMR spectroscopy, elemental analysis and/or HRMS.

13

Experimental Procedure for Preparation of 8: Compound 1 (418 mg, 1.27 mmol) was desilylated to form 2 as previously described (ref.^1b). To a mixture of CuI (3.5 mg) and Pd(PhCN)₂Cl₂ (20 mg) under argon was added argon-degassed THF (0.5 mL), toluene (0.5 mL), HN(i-Pr)₂ (0.17 mL). Then P(t-Bu)₃ (10% in hexane, 0.125 mL) was added and hereafter dibromide 7 (156 mg, 0.413 mmol), which resulted in a dark brown mixture. This mixture was transferred via a syringe to the flask containing solid 2. The mixture was subjected to ultrasonification at 30 °C for 4 h, whereupon it was filtered through a plug of silica (eluent: CH₂Cl₂). Column chromatography (SiO₂, CH₂Cl₂ → CH₂Cl₂-EtOAc 10:1) afforded 8 as a red-brown solid (253 mg, 84%). Mp 143-146 °C (decomp.). UV/Vis (CHCl₃): λ (ε/M^-1cm^-1): 294 (15200), 333 (15300), 378 (14500), 454 (39000) nm. ¹H NMR (300 MHz, CDCl₃): δ = 0.23 (s, 18 H), 3.83 (s, 6 H), 3.84 (s, 6 H), 5.65 (s, 2 H) ppm. ¹³C NMR (75 MHz, CDCl₃): δ = -0.2, 53.4 (two overlapping), 92.7, 96.1, 97.4, 101.8, 105.2, 112.5, 118.6, 130.6, 132.2, 148.0, 159.3, 159.7 ppm. MALDI-TOF-MS (matrix: 2,5-dihydroxy-benzoic acid): m/z = 728 [M⁺]. Anal. Calcd for C₃₂H₃₂O₈S₄Si₂ (729.03): C, 52.72; H, 4.42. Found: C, 52.96; H, 4.82.