Retro-Diels−Alder Reaction of 4H-1,2-Benzoxazines to Generateo-Quinone Methides:  Involvement of Highly Polarized Transition States

2007 ◽  
Vol 72 (26) ◽  
pp. 10088-10095 ◽  
Author(s):  
Hiromichi Sugimoto ◽  
Satoshi Nakamura ◽  
Tomohiko Ohwada
Keyword(s):  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Quinone Methides ◽  
Diels Alder Reaction

Organic transition states. V. The Diels-Alder reaction

1976 ◽  
Vol 98 (8) ◽  
pp. 2190-2198 ◽  
Author(s):  
R. E. Townshend ◽  
G. Ramunni ◽  
G. Segal ◽  
W. J. Hehre ◽  
L. Salem
Keyword(s):  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Organic Transition

QTAIM–DI–VISAB computational study on the Diels–Alder reaction of cyclopentadiene — On the nature of the so-called secondary orbital interactions

2008 ◽  
Vol 86 (7) ◽  
pp. 737-744 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
Wojciech Sokol
Keyword(s):  
Computational Study ◽  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Physical Organic Chemistry ◽  
Hydrogen Atoms ◽  
Endo Isomer ◽  
Orbital Interactions ◽  
Physical Organic ◽  
Diels Alder Reaction

We have undertaken a QTAIM–DI–VISAB computational study of the dimerization of cyclopentadiene (1), the archetypal example of a Diels–Alder reaction that has been studied experimentally and computationally. Secondary orbital interactions (SOIs) that have gained acceptance in the interpretation of stereoselectivities seen in many cycloaddition reactions have been used to account for the fact that the endo isomer was the kinetic product of the reaction. To this point, “classical” MO analyses along with a variety of arbitrarily assigned solid and dashed lines (solid lines and bold dashes for “primary” interactions and dashed and dotted lines to differentiate between different SOI schemes) have been used in an attempt to describe the bonding of the transition states. Yet, the existence of SOIs has been challenged. Our interest in applying QTAIM to fundamental chemical problems in physical organic chemistry, with the goal of refining our knowledge of the bonding in transition-states and ground-state molecules while obviating the need to use a variety of confusing arbitrarily assigned dashed and dotted lines, led us to a QTAIM–DI–VISAB computational study of the endo and exo dimerizations of 1 at the DFT B3PW91 and MPW1PW91 levels. We have characterized the bonding interactions between cyclopentadiene rings in the various transition states and show that “normal” bonds are present where SOIs have been considered to exist. There is no need to use different types of dashed and dotted lines. An analysis of the changes in atom energies revealed that the significant destabilization of the carbon atoms in achieving the TSs (potentially leading to a very high barrier) is ameliorated by a stabilization of the hydrogen atoms leading to the relatively low barrier for the D–A reaction.Key words: cyclopentadiene dimerization, bispericyclic transition states, DFT calculations, QTAIM–DI–VISAB analysis, bonding, atom energy analysis.

ChemInform Abstract: ORGANIC TRANSITION STATES. V. THE DIELS-ALDER REACTION

1976 ◽  
Vol 7 (27) ◽  
pp. no-no
Author(s):  
R. E. TOWNSHEND ◽  
G. RAMUNNI ◽  
G. SEGAL ◽  
W. J. HEHRE ◽  
L. SALEM
Keyword(s):  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Organic Transition

An Inverse Electron Demand Azo-Diels–Alder Reaction ofo-Quinone Methides and Imino Ethers: Synthesis of Benzocondensed 1,3-Oxazines

2018 ◽  
Vol 83 (8) ◽  
pp. 4775-4785 ◽  
Author(s):  
Dmitry V. Osipov ◽  
Vitaly A. Osyanin ◽  
Guzel’ D. Khaysanova ◽  
Elvira R. Masterova ◽  
Pavel E. Krasnikov ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Quinone Methides ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Electron Demand

scholarly journals Unusual Structure-Energy Correlations in Intramolecular Diels–Alder Reaction Transition States

Molecules ◽  
2014 ◽  
Vol 19 (10) ◽  
pp. 15535-15545 ◽  
Author(s):  
Justyna Żurek ◽  
Robert Rae ◽  
Martin Paterson ◽  
Magnus Bebbington
Keyword(s):  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Unusual Structure ◽  
Diels Alder Reaction
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