Novel Regio- and Stereoselective Dimerization of Terminal Alkynes Catalyzed by Rare-Earth Silylamide

Abstract

Rare-earth silylamide complex, Y[N(SiMe₃)₂]₃, was found to exhibit good catalyst activities for regio- and stereoselective dimerization of terminal aliphatic and aromatic alkynes in the presence of amine additives. Thus, using tertiary amine additives, particularly N(SiMe₃)₃, aliphatic terminal alkynes were efficiently converted to head-to-tail dimers. On the other hand, only Z-head-to-head dimers were obtained in high yields from aromatic alkynes with the catalyst and aromatic primary amines such as 4-ClC₆H₄NH₂.

Key words

dimerization - terminal alkynes - enynes - rare-earth silyl­amide - amine additives

References

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7

The reaction of 2a using three equivalents of Et₃N (15 mol%) gave 3a and 4a in 21 and 7% yields, respectively, with 49% conversion.

11

Although the products 3c and 4h were not isolated, they were identified by comparison of ¹H NMR spectra of their reaction mixtures with literature data. [2e] [f]