Do supra-antara paths really exist for 2 + 2 cycloaddition reactions? Analytical computation of the MC-SCF Hessians for transition states of ethylene with ethylene, singlet oxygen, and ketene

1988 ◽  
Vol 110 (18) ◽  
pp. 5993-5995 ◽  
Author(s):  
Fernando. Bernardi ◽  
Andrea. Bottoni ◽  
Massimo. Olivucci ◽  
Michael A. Robb ◽  
H. Bernard. Schlegel ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Transition States ◽  
Cycloaddition Reactions ◽  
Analytical Computation

Ene–Diene Transmissive Cycloaddition Reactions with Singlet Oxygen: The Vinylogous Gem Effect and Its Use for Polyoxyfunctionalization of Dienes

2014 ◽  
Vol 79 (4) ◽  
pp. 1818-1829 ◽  
Author(s):  
Angelika Eske ◽  
Bernd Goldfuss ◽  
Axel G. Griesbeck ◽  
Alan de Kiff ◽  
Margarethe Kleczka ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Cycloaddition Reactions

scholarly journals Short-Chained Anthracene Strapped Porphyrins and Their Endoperoxides

2020 ◽  
Author(s):  
Susan Callaghan ◽  
Keith Flanagan ◽  
John E. O'Brien ◽  
Mathias Senge
Keyword(s):  
Singlet Oxygen ◽  
1H Nmr ◽  
Absorption Spectroscopy ◽  
Cycloaddition Reactions ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
Polychromatic Light

The synthesis of short-chained anthracene-strapped porphyrins and their Zn(II)complexes are reported. The key synthetic step employed was a [2+2] condensation between a dipyrromethane and 2,2'-((anthracene-9,10-diylbis(methylene))bis(oxy))dibenzaldehyde. Following exposure to polychromatic light, self-sensitized singlet oxygen and the anthracene moieties underwent [4+2] cycloaddition reactions to yield the corresponding endoperoxides. 1H NMR studies demonstrate that the endoperoxide readily formed in chloroform-d and decayed at 85 °C. X-ray crystallography and absorption spectroscopy were used to confirm macrocyclic distortion in the parent strapped porphyrins and endoperoxides. Additionally, X-ray crystallography indicated that endoperoxide formation occurred exclusively on the outside face of the anthracene moiety.<br>

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