134055-33-7

Upstream product

• 134055-35-9 carbonyl{3-(diethyliminio)-1-ethoxy-2-methyl-4-phenyl-1-cyclopentene}tungstate 
• 132205-37-9 W(CO)5CN(C₂H₅)2CCH₃COC₂H₅CHCHC₆H₅ 

Relevant academic research and scientific papers

Organic Syntheses via Transition Metal Complexes, 54. - Cyclopentadienes from 1-Metalla-1,3-dienes and Alkynes by Cyclization of Intermediate 1-Metalla-1,3,5-trienes (Metal = Tungsten)

We report first examples of the formation of cyclopentadienes from a 1-metalla-1,3-diene LnM=C-C=C and an alkyne in cycloaddition multistep reactions.In a first step the alkyne Et2N-CC-Me (2) adds to the 1-metalla-1,3-diene (CO)5W=C(OEt)-CH=CHPh (1b) to give 1-metalla-1,3,5-trienes (CO)5W=C(NEt2)-CMe=C(OEt)-CH=CHPh (3b) and (CO)5W=C(OEt)-CH=C(NEt2)-CMe=CHPh (4b).In a second step 3b cyclizes to the cyclopentadiene complex 5, which has an η1 ylide-tye structure as established by an X-ray analysis.Hydrolysis of 5 leads to the formation of a 3-aminocyclopentenone 7.The 1-metalla-1,3,5-triene 4b yields a cyclopentadiene complex 8.In contrast to 5 the carbon skeleton of 8 has a connectivity different from that of the C3 unit of the 1-metalla-1,3-diene 1.Key Words: Cyclopentadienes, synthesis of / Cycloadditions of 1-metalla-1,3-dienes and alkynes / 1-Metalla-1,3,5-trienes of tungsten, cyclization to cyclopentadiene complexes / η1-Cyclopentadiene tungsten complexes / Aminocarbene complexes of chromium and tungsten