Tert-alkyl-alkynyl coupling

No general method is available for tert-alkyl-alkynyl-coupling based on sodium or lithium alkynylide reagents because of prevalent elimination. However, trialkyn-ylalanes obtained from the corresponding alkynyllithiums and anhydrous aluminum trichloride undergo clean reaction with tert-halides to produce rert-alkyl substituted... 

The efficiency of activation of tert-alkyl fluorides by alkylaluminums can be extended to the successful tert-alkyl-alkynyl coupling with dialkylaluminum acetylides, in which selective transfer of the alkynyl group smoothly occurred to give (3) under mild conditions (Scheme 6.1). 

A direct procedure for tert-alkyl-alkynyl coupling using tert-alkyl chloride or bromide was reported by Negishi and Baba. The reaction provides successive geminal alkyl-alkynylation of ketones (Scheme 6.6) [6]. 

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