An unusual cobalt-mediated cleavage of a hindered alkyne

✍ Scribed by Naoto Hayashi; Douglas M Ho; Robert A Pascal Jr.

• Book ID: 104210399
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 156 KB
• Volume: 41
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)00667-5

✦ Synopsis

When 1-(pentaphenylphenyl)-2-phenylacetylene (1) is heated with (Z 5 -cyclopentadienyl)dicarbonylcobalt, 1,2,3,4-tetraphenyl¯uorene (3) and related minor products are formed rather than the expected tetraarylcyclobutadiene. The formation of 3 requires that a seven-carbon fragment (formally a phenylcarbyne) must be lost. Two minor products, however, result from intramolecular cyclization of the alkyne and these two retain all of the carbons from the starting material.