scholarly journals Dynamic effects in the didehydro-Diels-Alder (DDDA) reaction of enyne-ketoenes: 50% stepwise bond formation in spite of concerted transition state

2017 ◽  
Vol 30 (9) ◽  
pp. e3732
Author(s):  
Anup Rana ◽  
Indrajit Paul ◽  
Michael Schmittel
Keyword(s):  
Transition State ◽  
Bond Formation ◽  
Diels Alder ◽  
Dynamic Effects

Ab initio Cs transition state for the Diels-Alder reaction of acetylene and butadiene

1990 ◽  
Vol 55 (12) ◽  
pp. 3804-3807 ◽  
Author(s):  
James M. Coxon ◽  
Stephen T. Grice ◽  
Robert G. A. R. Maclagan ◽  
D. Quentin McDonald
Keyword(s):  
Transition State ◽  
Ab Initio ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

scholarly journals Understanding the Bond Formation in Hetero-Diels-Alder Reactions. An ELF Analysis of the Reaction of Nitroethylene with Dimethylvinylamine

2012 ◽  
Vol 16 (19) ◽  
pp. 2343-2351 ◽  
Author(s):  
Luis R. Domingo ◽  
Patricia Perez ◽  
M. Jose Aurell ◽  
Jose A. Saez
Keyword(s):  
Bond Formation ◽  
Diels Alder

Selectivity in carbon–carbon coupling reactions at palladium(IV) and platinum(IV)

2019 ◽  
Vol 97 (7) ◽  
pp. 529-537 ◽  
Author(s):  
Richard J. Puddephatt
Keyword(s):  
Activation Energy ◽  
Transition State ◽  
Computational Study ◽  
Bond Formation ◽  
Reductive Elimination ◽  
Organometallic Complexes ◽  
Axial Position ◽  
Coupling Reactions ◽  
Methyl Group ◽  
Trigonal Bipyramidal

The isomerization and reductive elimination reactions from octahedral organometallic complexes of palladium(IV) and platinum(IV) usually occur through five-coordinate intermediates that cannot be directly detected. This paper reports a computational study of five-coordinate complexes of formulae [PtMe3(bipy)]+, [PtMe2Ph(bipy)]+, and [PtMe(CH2CMe2C6H4)(bipy)]+ (M = Pd or Pt, bipy = 2,2′-bipyridine), particularly with respect to reactivity and selectivity in reductive elimination. All of the complexes are predicted to have square pyramidal structures with the bipy and two R groups in the equatorial positions and one R group in the axial position, and axial–equatorial exchange occurs by a pairwise mechanism, with the transition state having a pinched trigonal bipyramidal (PTBP) stereochemistry, with one nitrogen and two R groups in the trigonal plane. The activation energy for isomerization is lower than that for reductive elimination in all cases. For the complexes [MMe2Ph(bipy)]+, the activation energies for reductive elimination with Me–Me or Me–Ph coupling are similar. For the complexes [MMe(CH2CMe2C6H4)(bipy)]+, the reductive elimination with Me–C6H4 bond formation from the isomer with the methyl group in the axial position is predicted and is attributed to it having the best conformation of the Me and C6H4 groups for C–C bond formation. In all cases, the selectivity for reductive elimination is similar for M = Pd or Pt, but reactivity is higher for M = Pd. The relevance of this work to selectivity in catalysis is discussed.

ChemInform Abstract: First Evidence of a Chair-Boat-Boat Transition State in the Transannular Diels-Alder Reaction.

ChemInform ◽  
2010 ◽  
Vol 25 (38) ◽  
pp. no-no
Author(s):  
Y. L. DORY ◽  
C. OUELLET ◽  
S. BERTHIAUME ◽  
A. FAVRE ◽  
P. DESLONGCHAMPS
Keyword(s):  
Transition State ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction
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