Regiochemistry of the Condensation of 2-Aroyl-cyclohexanones and 2-Cyanoacetamide: 13C-Labeling Studies and Semiempirical MO Calculations

2012 ◽  
Vol 77 (17) ◽  
pp. 7355-7363 ◽  
Author(s):  
Oscar P. J. van Linden ◽  
Maikel Wijtmans ◽  
Luc Roumen ◽  
Lonneke Rotteveel ◽  
Rob Leurs ◽  
...  
Keyword(s):  
Mo Calculations ◽  
13C Labeling ◽  
Semiempirical Mo Calculations

New Macrocyclic Ligands. XI. Synthesis, X-Ray Structure and Computational Studies of a New N2O4S2-Heteroatom Cage

2000 ◽  
Vol 53 (9) ◽  
pp. 799 ◽  
Author(s):  
Ian M. Atkinson ◽  
David C. R. Hockless ◽  
Leonard F. Lindoy ◽  
Owen A. Matthews ◽  
George V. Meehan ◽  
...  
Keyword(s):  
Single Crystals ◽  
Structure Determination ◽  
Macrocyclic Ligands ◽  
Computational Studies ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations ◽  
Cage Molecule ◽  
Helical Configuration

The synthesis and single-crystal X-ray structure determination of a new cage molecule containing four oxygen, two sulfur, and two nitrogen heteroatoms are described. The structure determination shows that a twist occurs about each (tribenzyl) nitrogen bridgehead so that an overall helical configuration within putative quasi-2 symmetry is generated; both nitrogens have their lone pairs orientatedexo. Single crystals of this compound are homochiral. Semiempirical MO calculations have been used to probe the topological rigidity of this system relative to the more symmetrical analogue incorporating six oxygen and two nitrogen heteroatoms reported previously. The introduction of the sulfur atoms appears to restrict the facile interconversion between enantiomers that was predicted for the N2O6-analogue mentioned above. The implications of the structure for the design of larger cages are discussed.

Semiempirical MO calculations on symmetry governed reactions

1974 ◽  
Vol 34 (3) ◽  
pp. 213-224 ◽  
Author(s):  
Patrick Coffey ◽  
Karl Jug
Keyword(s):  
Mo Calculations ◽  
Semiempirical Mo Calculations
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