693287-64-8Relevant academic research and scientific papers
A re-evaluation of the electrophilic substitution reactions of the Ramirez ylide
Higham, Lee J.,Muldoon, Jimmy,Kelly, P. Gabriel,Corr, David M.,Mueller-Bunz, Helge,Gilheany, Declan G.
, p. 8780 - 8785 (2008/03/13)
(Chemical Equation Presented) Cyclopentadienylidenetriphenylphosphorane (the Ramirez ylide), unexpectedly and contrary to a number of earlier reports, has been shown to be like pyrrole in undergoing electrophilic substitution on the cyclopentadienide ring
A novel azulene synthesis from the Ramirez ylide involving two different modes of its reaction with activated alkynes
Higham, Lee J.,Kelly, P. Gabriel,Corr, David M.,Mueller-Bunz, Helge,Walker, Brian J.,Gilheany, Declan G.
, p. 684 - 685 (2007/10/03)
The Ramirez ylide undergoes electrophilic substitution with acetylenedicarboxylates to form Z and E adducts. The latter can react by cycloaddition with another equivalent of the alkyne to provide a new route to novel tetra-substituted azulenes, which show
{(E)- and {(Z)-2-[α,β-bis(methoxycarbonyl)vinyl]cyclopentadien-1-ylidene} triphenylphosphorane
Higham, Lee J.,Kelly, P. Gabriel,Mueller-Bunz, Helge,Gilheany, Declan G.
, p. o308-o311 (2007/10/03)
The Ramirez ylide undergoes electrophilic substitution with dialkyl acetylenedicarboxylates, yielding a mixture of the Z and E adducts. The crystal structure analyses of the two adducts formed using dimethylacetylene, viz. dimethyl (E)-and (Z)-1-[2-(triphenylphosphoranylidene)cyclopentadien-1-yl]ethylenedicarboxylate, both C29H25O4P, explain an unusual chemical shift observed for the vinyl H atom of the Z adduct, which had previously precluded a definitive assignment of the isomers. In addition, the structures explain why only one of the isomers reacts further with acetylene esters to produce azulenes with a rare substitution pattern.
