Alkynyl Sulfides as Dienophilesin Cobalt-Catalyzed Diels-Alder Reactions

Abstract

The cobalt(I)-catalyzed cycloaddition of alkynyl sulfides with1,3-dienes can be realized at ambient temperatures. In combinationwith a mild oxidation step various polysubstituted and functionaliseddiaryl sulfides can be synthesized in good overall yields.

Key words

alkynes - catalysis - cobalt - Diels-Alderreactions - sulfides

References

• For reviews concerning alkynyl sulfoxidesand alkynyl sulfones as dienophiles in Diels-Alder reactions,see:
• 1a Lee AWM. Chan WH. Top.Curr. Chem.  1997,  190:  103 
• 1b Lee AWM. Chan WH. Zhang HK. Xia PF. Curr.Org. Chem.  2003,  7:  573 
• 2a Sauer J. Heldmann DK. Hetzenegger J. Krauthan J. Sichert H. Schuster J. Eur.J. Org. Chem.  1998,  2885 
• 2b Nakayama J. Yamaoka S. Nakanishi T. Hoshino M. J. Am. Chem. Soc.  1988,  110:  6598 
• For recent cobalt(I)-catalysed Diels-Alderreactions with functionalised non-activated starting materials,see:
• 3a

  Hilt, G.; Smolko, K.I. Angew. Chem. Int. Ed. 2003, 43, 2797; Angew.Chem. 2003, 115,2901.

• 3b Hilt G. Smolko KI. Synthesis  2002,  686 
• 3c Hilt G. Smolko KI. Synlett  2002,  1081 
• For the synthesis of alkyl alkynylsulfides, see:
• 5a Voets M. Smet M. Dehaen W. J.Chem. Soc., Perkin Trans I  1999,  1473 
• 5b Woodgate PD. Sutherland HS. Rickard CEF. J. Organomet. Chem.  2001,  627:  206 
• For the synthesis of aryl alkynylsulfides, see:
• 6a Maruyama H. Shiozaki M. Oida S. Hiraoka T. Tetrahedron Lett.  1985,  26:  4521 
• 6b Kabanyane ST. MaGee DI. CanJ. Chem.  1992,  70:  2758 

4

Small amounts of reduction products,such as alkenyl sulfides, were detected by GC-MS analysis.