Lithium (1-Pentynyl)(2-tri-n-butylstannylvinyl)cuprate

[-]  · C19H36CuLiSn  · Lithium (1-Pentynyl)(2-tri-n-butylstannylvinyl)cuprate  · (MW 453.75)

(mixed organocuprate; introduces angular acetylene equivalent to enones via vinylstannanes)

Preparative Method: prepared in situ by first monolithiating trans-1,2-Bis(tributylstannyl)ethylene with n-Butyllithium in THF at -78 °C, then transferring the anionic solution via cannula to a mixture of 1-Pentynylcopper(I) and Hexamethylphosphorous Triamide at -40 °C.1

Handling, Storage, and Precautions: air- and moisture-sensitive. Use in a fume hood.

Lithium (1-pentynyl)(2-tri-n-butylstannylvinyl)cuprate (1) undergoes 1,4-addition to a,b-enones in high yields.1 The resulting addition products can then be readily transformed into terminal alkynes with Lead(IV) Acetate in acetonitrile. This sequence provides a two-step method for the introduction of angular acetylenes (eqs 1 and 2).

Related Reagents.

1-Hexynylcopper(I); Lithium (1-Hexynyl)(2-tri-n-butylstannylvinyl)cuprate; 1-Pentynylcopper(I); 1-Pentynylcopper(I)-Hexamethylphosphorous Triamide.

1. Corey, E. J.; Wollenberg, R. H. JACS 1974, 96, 5581.

Matthew E. Voss

The Du Pont Merck Pharmaceutical Company, Wilmington, DE, USA

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