Synthesis of Aryl Stannanes from Silyl Triflates via Aryne Intermediates

Abstract

Aryl stannanes are easily accessible from o-silylated aryl triflates in the presence of KF and Bu₃SnH. The corresponding arynes are formed in situ, and undergo clean hydrostannation to give a mixture of the regioisomeric aryl stannanes. The whole reaction sequence can also be carried out as a one-pot reaction under microwave irradiation.

arynes - aryl stannanes - hydrostannation - one-pot reaction - Stille coupling

References and Notes

1a Stille JK. Angew. Chem., Int. Ed. Engl.  1986,  25:  508 ; Angew. Chem. 1986, 98, 504

1b Davies AG. In Comprehensive Organometallic Chemistry II   Vol. 2:  Pergamon; New York: 1995.  p.217 

1c Davies AG. Organotin Chemistry   VCH; Weinheim: 1997. 

For reviews, see:

2a Smith ND. Mancuso J. Lautens M. Chem. Rev.  2000,  100:  3257 

2b Trost BM. Ball ZT. Synthesis  2005,  853 ; and references cited therein

3 Hayashi T. Ishigedani M. Tetrahedron  2001,  57:  2589 

4a Gilman H. Rosenberg SD. J. Am. Chem. Soc.  1953,  75:  2507 

4b Earbon C. Seconi G. J. Chem. Soc., Perkin Trans. 2  1976,  925 

4c Iddon B. Lim BL. J. Chem. Soc., Perkin Trans. 1  1983,  271 

5a Knochel P. Singer RD. Chem. Rev.  1993,  93:  2117 

5b Zhu X. Blough BE. Caroll FI. Tetrahedron Lett.  2000,  41:  9219 

5c Gosmini C. Perichon J. Org. Biomol. Chem.  2005,  216 

6a Kosugi M. Shiminu K. Ohtani A. Migita T. Chem. Lett.  1981,  829 

6b Kosugi M. Ohya T. Migita T. Bull. Chem. Soc. Jpn.  1983,  56:  3855 

7a Lockhart MT. Chopa AB. Rossi RA.
J. Organomet. Chem.  1999,  582:  229 

7b Chopa AB. Lockhart MT. Silbestri G. Organometallics  2001,  20:  3358 

7c Chopa AB. Lockhart MT. Silbestri G. Organometallics  2000,  19:  2249 

8a Yoshida H. Tanino K. Ohshita J. Kunai A. Angew. Chem. Int. Ed.  2004,  43:  5052 ; Angew. Chem. 2004, 116, 5162

8b Yoshida H. Tanino K. Ohshita J. Kunai A. Chem. Commun.  2005,  5678 

9a Kazmaier U. Schauß D. Pohlman M. Org. Lett.  1999,  1:  1017 

9b Kazmaier U. Pohlman M. Schauß D. Eur. J. Org. Chem.  2000,  2761 

9c Kazmaier U. Schauß D. Pohlman M. Raddatz S. Synthesis  2000,  914 

9d Kazmaier U. Schauß D. Raddatz S. Pohlman M. Chem. Eur. J.  2001,  7:  456 

9e Braune S. Kazmaier U.
J. Organomet. Chem.  2002,  641:  26 

9f Braune S. Pohlman M. Kazmaier U. J. Org. Chem.  2004,  69:  468 

9g Kazmaier U. Dörrenbächer S. Wesquet A. Lucas S. Kummeter M. Synthesis  2007,  320 

9h Lakshmi BV. Kazmaier U. Synlett  2010,  407 

10a Himeshima Y. Sonoda T. Kobayashi H. Chem. Lett.  1983,  1211 

10b Peña D. Escudero S. Pérez D. Guitián E. Castedo L. Angew. Chem. Int. Ed.  1998,  37:  2659 ; Angew. Chem. 1998, 110, 2804. For this and other methods to generate arines and for applications see the following reviews:

10c Pellissier H. Santelli M. Tetrahedron  2003,  59:  701 

10d Yoshida H. Ohshita J. Kunai A. Bull. Chem. Soc. Jpn.  2010,  83:  199 

11a Himeshima Y. Kobayashi H. Sonoda T. J. Am. Chem. Soc.  1985,  107:  5286 

11b Peña D. Pérez D. Guitián E. Castedo L. J. Org. Chem.  2000,  65:  6944 

11c Peña D. Cobas A. Pérez D. Guitián E. Synthesis  2002,  1454 

11d Zhijian L. Larock RC. J. Org. Chem.  2006,  71:  3198 

12 Yoshida H. Terayama T. Ohshita J. Kunai A. Chem. Commun.  2004,  1980 

13 Lee K. Gallagher WP. Toskey EA. Chong W. Maleczka RE. J. Organomet. Chem.  2006,  691:  1462 

14 Moriello AS. Balas L. Ligresti A. Cascio MG. Durand T. Morera E. Ortar G. Di Marzo V. J. Med. Chem.  2006,  49:  2320 

15

General procedure for the synthesis of aryl stannanes 2: In a Schlenk flask, silyl triflate 1 (0.33 mmol) was dissolved in THF (3 mL) and hydroquinone (0.033 mmol, 3.6 mg), tributyltin hydride (0.10 mL, 0.39 mmol), 18-crown-6 (174 mg, 0.660 mmol), and KF (37 mg, 0.66 mmol) were added sequentially. The resulting mixture was stirred at 20 ˚C for 2-3 h. The reaction mixture was then diluted with ethyl acetate, filtered through Celite, and concentrated. Column chromatography on silica gel (pentane or hexane with 1 vol% Et₃N) gave aryl stannanes 2 as colorless oils.
One-pot synthesis of phenyl stannane and Stille coupling with benzoyl chloride: In a microwave vial, silyl triflate 1a (100 mg, 0.330 mmol) was dissolved in THF (2.0 mL) and hydroquinone (0.033 mmol, 3.6 mg), tributyltin hydride (0.089 mL, 0.33 mmol), 18-crown-6 (174 mg, 0.660 mmol), and KF (37 mg, 0.66 mmol) were added sequentially. The resulting mixture was subjected to microwave irradiation for 15 min at 100 ˚C (max. 200 W). Separately, in a round-bottom flask, [(allyl)PdCl]₂ (0.0033 mmol, 1.2 mg) and Ph₃P (3.5 mg, 0.013 mmol) were dissolved in THF (2 mL) and stirred at r.t. for 5 min. The resulting solution and benzoyl chloride (70 mg, 0.49 mmol) were added to the crude reaction mixture in the microwave vial, which was subjected to further microwave irradiation at 150 ˚C for 30 min (max. 200 Watt). The reaction mixture was diluted with saturated aq KF (3 mL) and stirred for 30 min. The mixture was extracted with Et₂O and the combined organic layers were dried with NaSO₄, filtered and concentrated under reduced pressure. Purification of the residue by column chromatography on silica gel (hexane-EtOAc, 19:1) afforded benzophenone as a colorless solid (37 mg, 60%).