Palladium-Catalyzed Cross-Coupling of Alkynylzincs with Allylic Electrophiles: An Efficient and Selective Synthesis of Stereo- and Regio-Defined 1,4-Enynes

Abstract

Clean and high-yielding cross-coupling of alkynylzincs with allylic chlorides, bromides, or acetates exhibiting 98% regio- and stereoselectivity can be achieved by using 1 mol% of ­Pd(DPEphos)Cl₂ and either 1:1 THF-DMF or pure DMF. This reaction provides a satisfactory route to 1,4-enynes via Pd-catalyzed alkynyl-allyl coupling.

Key words

Pd-catalyzed alkynyl-allyl coupling - 1,4-enynes - alkynylzincs - allylic electrophiles - Pd(DPEphos)Cl₂

References

• For extensive reviews of Pd-catalyzed cross-coupling, see
• 1a Handbook of Organopalladium Chemistry for Organic Synthesis   Vols. 1 and 2, Part III:  Negishi E. Wiley-Interscience; New York: 2002.  p.215-1119  
• 1b Metal-Catalyzed Cross-Coupling Reactions   Vols. 1 and 2:  de Meijere A. Diederich F. Wiley-VCH; Weinheim: 2004. 
• 2 For a recent review on Pd-catalyzed alkynylation, see, Negishi E. Anastasia L. Chem. Rev.  2003,  103:  1979 
• 3a Florio S. Ronzini L. Sgarra R. Gazz. Chim. Ital.  1994,  124:  77 
• 3b Cui D.-M. Hashimoto N. Ikeda S. Sato Y. J. Org. Chem.  1995,  60:  5752 
• 4a Danheiser RL. Gee SK. J. Org. Chem.  1984,  49:  1672 
• 4b Negishi E. Zhang Y. Cederbaum FE. Webb MB. J. Org. Chem.  1986,  51:  4080 
• 4c Jeffery T. Tetrahedron Lett.  1989,  30:  2225 
• 4d Matucera ED. Erin AS. Kung AL. Russ. J. Org. Chem.  1997,  33:  1061 
• 5 Yamanoi S. Imai T. Matsumoto T. Suzuki K. Tetrahedron Lett.  1997,  38:  3031 
• 6a Perez I. Sestelo JP. Sarandeses LA. Org. Lett.  1999,  1:  1267 
• 6b Perez I. Sestelo JP. Sarandeses LA. J. Am. Chem. Soc.  2001,  123:  4155 
• 7 Qian M. Negishi E. Tetrahedron Lett.  2005,  46:  2927 
• For recent papers from the authors’ group reporting favorable effects of chelating phosphines in Pd-catalyzed cross-coupling, see:
• 8a Shi J. Zeng X. Negishi E. Org. Lett.  2003,  5:  1825 
• 8b Zeng X. Hu Q. Qian M. Negishi E. J. Am. Chem. Soc.  2003,  125:  13636 
• 8c Shi J. Negishi E. J. Organomet. Chem.  2003,  687:  518 
• 8d Zeng X. Qian M. Hu Q. Negishi E. Angew. Chem. Int. Ed.  2004,  43:  2259 
• 8e Tan Z. Negishi E. Angew. Chem. Int. Ed.  2004,  43:  2911 
• 8f Qian M. Huang Z. Negishi E. Org. Lett.  2004,  6:  1531 
• 8g Novak T. Tan Z. Liang B. Negishi E. J. Am. Chem. Soc.  2005,  127:  2838 
• 8h Huang Z. Qian M. Babinski DT. Negishi E. Organometallics  2005,  24:  475 
• 9 Kranenburg M. van der Burgt YEM. Kamer PCJ. van Leeuwen PWNM. Goubitz K. Fraanje J. Organometallics  1995,  14:  3081 
• 10 Hayashi T. Konishi M. Kobori Y. Kumada M. Higuchi T. Hirotsu K. J. Am. Chem. Soc.  1984,  106:  158