4087-50-7Relevant articles and documents
Geminal repulsion disrupts Diels–Alder reactions of geminally substituted cyclopentadienes and 4H-pyrazoles
Levandowski, Brian J.,Abularrage, Nile S.,Raines, Ronald T.
, (2021)
We have experimentally and computationally explored the sluggish Diels–Alder reactivities of the geminally substituted 5,5-dimethylcyclopentadiene and 5,5-dimethyl-2,3-diazacyclopentadiene (4,4-dimethyl-4H-pyrazole) scaffolds. We found that geminal dimethylation of 1,2,3,4-tetramethylcyclopentadiene to 1,2,3,4,5,5-hexamethylcyclopentadiene decreases the Diels–Alder reactivity towards maleimide by 954-fold. Quantum mechanical calculations revealed that the decreased Diels–Alder reactivities of gem-dimethyl substituted cyclopentadienes and 2,3-diazacyclopentadienes are not a consequence of unfavorable steric interactions between the diene and dienophile as reported previously, but a consequence of the increased repulsion within the gem-dimethyl group in the transition state. The findings have implications for the use of cyclopentadienes in “click” chemistry.
Molecular Solar Thermal Batteries through Combination of Magnetic Nanoparticle Catalysts and Tailored Norbornadiene Photoswitches
Lorenz, Patrick,Luchs, Tobias,Hirsch, Andreas
supporting information, p. 4993 - 5002 (2021/02/26)
Cobalt catalysts are immobilized on the surface of iron oxide nanoparticles for the preparation of highly active quasi-homogeneous catalysts toward an efficient release of photochemically stored energy in norbornadiene-based photoswitches. The facile sepa
PHASE TRANSFER CATALYZED TERT-ALKYLATIONS OF CYCLOPENTADIENE AND INDENE: INDICATIONS FOR SET PROCESSES
Dehmlow, Eckehard V.,Bollmann, Christof
, p. 5773 - 5776 (2007/10/02)
Scope and mechanism of the PTC tert-alkylation of cyclopentadienide anion have been investigated.On the side of the anion, the reaction is limited to cyclopentadiene and indene, whereas many tertiary as well as secondary and primary alkylating agents can be employed.Hexamethylcyclopentadiene 8, for instance, is available easily.Tert-alkylations of this type are more effective if 4,4'-bipyridinium salts are present in addition to a phase transfer catalyst.The reactions involve probably an initial single electron transfer (SET) step.