Transformation of a 1‐Zirconacyclopent‐3‐yne, a Five‐Membered Cycloalkyne, into a 1‐Zirconacyclopent‐3‐ene and Formal “1‐Zirconacyclopenta‐2,3‐dienes”

Abstract

Alkyne, alkene, and “allene”? A stable five-membered metallacycloalkyne 1 with alkylidene moieties was treated with an alkali metal to give a dianionic species 2, which was transformed into a 1-zirconacyclopent-3-ene complex by protonation. The alkylation of 2 afforded zirconocene–η4-1,3-enyne complexes 3, which can be regarded as formal “1-zirconacyclopenta-2,3-dienes”. Ar=4-EtC6H4; R=Me, Me3Sn. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z800739_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.