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Synthesis of 1,2,3,4,5‐Penta(methoxycarbonyl)cyclopentadienides through Electrocyclic Ring Closure and Ring Contraction Reactions
Author(s) -
Salikov Rinat F.,
Trainov Konstantin P.,
Platonov Dmitry N.,
Belyy Alexander Yu.,
Tomilov Yury V.
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800732
Subject(s) - chemistry , dimethyl acetylenedicarboxylate , sodium borohydride , cycloaddition , pyridine , electrocyclic reaction , pyridinium , medicinal chemistry , ring (chemistry) , stereochemistry , organic chemistry , catalysis
The mechanism for the reaction of dimethyl malonate with dimethyl acetylenedicarboxylate in the presence of pyridine and acetic acid to form isomeric octa(methoxycarbonyl)cycloheptadienes was established. The formation of intermediary N ‐[di(methoxycarbonyl)vinyl]pyridinium acetate was proven by means of NMR spectroscopy. On the basis of the established mechanism, dimethyl dibromosuccinate was proposed to be used instead of dimethyl acetylenedicarboxylate. A novel method for the synthesis of penta(methoxycarbonyl)cyclopentadienylsodium through the reduction of hepta(methoxycarbonyl)cycloheptatriene with sodium borohydride, electrocyclic ring contraction and retro‐[2+2]‐cycloaddition was developed.