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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
Author(s) -
Geng Weizhi,
Wang Chao,
Guang Jie,
Hao Wei,
Zhang WenXiong,
Xi Zhenfeng
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201300416
Subject(s) - cyclopentadiene , chemistry , intramolecular force , intermolecular force , diiodomethane , medicinal chemistry , photochemistry , stereochemistry , organic chemistry , molecule , catalysis , surface energy
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 CH 2 I 2 , and two different or identical alkynes. Two alkynes or one diyne undergo Cp 2 Zr II ‐mediated (Cp=η 5 ‐C 5 H 5 ) 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 H )‐pyrimidinone (DMPU), with CH 2 I 2 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 [( 4R Cp) 2 ZrCl 2 ] and [( 4R Cp) 2 ZrR′ 2 ] (R′=Me, Et, or n 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.