Palladium-Catalyzed Cross-Coupling Reaction of Arylboronic Acids with Chloroformate or Carbamoyl Chloride

Abstract

The first palladium-catalyzed cross-coupling reaction between substituted arylboronic acids and chloroformate or carbamoyl chloride is described. One-carbon homologation from arylboronic acids was achieved to give corresponding esters or amides in good yields.

Key words

cross-coupling reaction - palladium - boronic acid - arylcarboxylic ester - arylcarboxamide

References

• 1 Thompson DJ. In Comprehensive Organic Synthesis   Vol. 4:  Trost BM. Fleming I. Pergamon Press; Oxford: 1991.  p.1028-1035  
• 2a Colquhoun HM. Thompson DJ. Twigg MV. Carbonylation   Plenum Press; New York: 1991.  p.111-157  
• 2b Schoenberg A. Heck RF. J. Org. Chem.  1974,  39:  3327 
• 3a Lew A. Krutzik PO. Hart ME. Chamberlin AR. J. Comb. Chem.  2002,  4:  95 
• 3b Larhend M. Hallberg A. Drug Discov. Today  2001,  6:  406 
• 3c Strauss CR. Trainor RW. Aust. J. Chem.  1995,  48:  1665 
• 4a Corey EJ. Hegedus LS. J. Am. Chem. Soc.  1969,  91:  1233 
• 4b Crandall JK. Mickaely WJ. J. Organomet. Chem.  1973,  51:  375 
• 5 Kaiser N.-FK. Hallberg A. Larhed M. J. Comb. Chem.  2002,  4:  109 
• 6 Collman JP. Winter SR. Komoto RG. J. Am. Chem. Soc.  1976,  95:  249 
• 7 Lindsay CM. Widdowson DA. J. Chem. Soc., Perkin Trans. 1  1988,  569 
• 8 Cunico RF. Maity BC. Org. Lett.  1999,  4:  4357 
• 9 Hosoi K. Nozaki K. Hiyama T. Org. Lett.  2002,  4:  2849 
• 10 Balas L. Jousseaume B. Shin H. Berlhac J.-B. Wallian F. Organometallics  1991,  10:  366 
• 11a Miyaura N. Suzuki A. Chem. Rev.  1995,  95:  2457 
• 11b Suzuki A. J. Organomet. Chem.  1999,  576:  147 
• 11c Hassan J. Sevignon M. Gozzi C. Schulz E. Lemaire M. Chem. Rev.  2002,  102:  1359 
• 12 Chen H. Deng M.-Z. Org. Lett.  2000,  2:  1649 
• 13 Liu X.-X. Deng M.-Z. Chem. Commun.  2002,  6:  622 
• 14 Duan Y.-Z. Deng M.-Z. Tetrahedron Lett.  2003,  44:  3423 

15

General Procedure: m-Tolylboronic acid (82 mg, 0.6 mmol), Pd(PPh₃)₄ (17 mg, 0.015 mmol), Cu₂O (4 mg, 0.028 mmol), K₃PO₄·3H₂O (439 mg, 1.65 mmol) were placed in a flask under Ar atmosphere. Toluene (4 mL) and ethyl chloroformate (50 µL, 0.5 mmol) were added and the reaction mixture was stirred at 80 °C for 24 h. The reaction mixture was allowed to cool to r.t., and H₂O (5 mL) was added. The mixture was then extracted with Et₂O (3 × 10 mL). The combined organic layer was washed with brine (3 × 10 mL), dried over MgSO₄ and concentrated. The residue was chromatographed on silica gel (elution with hexanes-EtOAc = 30:1) to afford the corresponding ethyl arylcarboxylic ester 3a. ¹H NMR (300 MHz, CDCl₃-TMS): δ = 7.70-7.86 (m, 2 H), 7.30-7.35 (m, 2 H), 4.36 (q, J = 7.2 Hz, 2 H), 2.40 (s, 3 H), 1.39 (t, J = 7.2 Hz, 3 H) ppm. EIMS: m/z (%) = 164 (29) [M⁺], 119 (100), 91 (51), 164 (29), 136 (26), 65 (23), 120 (16), 89 (12), 63 (10). IR (neat): 2983, 1719, 1280, 1201, 1107, 1084, 746, 684 cm^-1. Anal. Calcd for C₁₀H₁₂O₂: C, 73.17; H, 7.32; Found: C, 73.03; H, 7.45.