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A New and Efficient Synthesis of Highly Functionalized (Triphenylphosphoranylidene)cyclopentadienes with Zwitterionic Resonance Structures
Author(s) -
Alizadeh Abdolali
Publication year - 2005
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200590012
Subject(s) - chemistry , aryl , nitro , resonance (particle physics) , medicinal chemistry , carbon 13 nmr , diene , proton nmr , stereochemistry , combinatorial chemistry , organic chemistry , alkyl , physics , natural rubber , particle physics
Different esters of 2‐aryl‐4‐hydroxy‐3‐nitro‐5‐(triphenylphosphoranylidene)cyclopenta‐1,3‐diene‐1‐carboxylates 1 were prepared in excellent yields from the 1 : 1 : 1 reaction between Ph 3 P, dialkyl acetylenedicarboxylates 2 , and (substituted) 2‐(nitroethenyl)benzenes 3 ( Scheme 1 ). The structures of the highly functionalized compounds 1 were corroborated spectroscopically (IR, 1 H‐, 13 C‐, 31 P‐NMR, EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed ( Scheme 2 ).