1, 2, 3, 4‐Tetrasubstituted Cyclopentadienes and Their Applications for Metallocenes: Efficient Synthesis through Zirconocene‐ and CuCl‐Mediated Intermolecular Coupling of Two Alkynes and One Diiodomethane. Issue 26 (2nd May 2013)

• Record Type: Journal Article
• Authors: Geng, Weizhi; Wang, Chao; Guang, Jie; Hao, Wei; Zhang, Wen‐Xiong; Xi, Zhenfeng
• Is Part Of: Chemistry. Volume 19:Issue 26(2013)
• Page Start: 8657
• Page End: 8664
• Publication Date: 2013-05-02
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201300416
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>1, 2, 3, 4‐Tetrasubstituted cyclopentadienes and indene derivatives with identical or different substituents were obtained in good to excellent isolated yields through a zirconocene‐ and CuCl‐mediated intermolecular coupling process. This synthetic procedure involved three organic partners, including one CH₂I₂, and two different or identical alkynes. Two alkynes or one diyne undergo Cp₂Zr^II‐mediated (Cp=η⁵‐C₅H₅) pair‐selective reductive coupling to afford the corresponding zirconacyclopentadiene derivatives, which react, in the presence of CuCl and 1, 3‐dimethyl‐3, 4, 5, 6‐tetrahydro‐2(1 <italic>H</italic>)‐pyrimidinone (DMPU), with CH₂I₂ through intermolecular followed by intramolecular coupling to afford the cyclopentadiene derivatives. An application of the prepared tetrasubstituted cyclopentadiene derivatives was demonstrated by the facile synthesis of the corresponding zirconocene complexes [(^4RCp)₂ZrCl₂] and [(^4RCp)₂ZrR′₂] (R′=Me, Et, or <italic>n</italic>Bu). The unique 1, 2, 3, 4‐tetrasubstituted cyclopentadiene ligands and the corresponding metallocenes are expected to have further applications in organometallic chemistry and organic synthesis.</p> </abstract>