Unusually large scalar coupling between geminal protons in saturated pyrimidine

View/ Open
Date
2018-04-29Author
Mazzola, Eugene P.
Gutierrez, Osvaldo
Fraenkel, Gideon A.
Chow, Albert
Doyle, Michael P.
Mandler, Michael D.
Dykstra, Ryan
Garg, Deeya
Ridge, Clark D.
Metadata
Show full item recordAbstract
An unusually large geminal coupling has been observed in a stereochemically
rigid system that permits a favorable coupling alignment between the methylene
protons and an adjacent carbon-carbon double bond. Such couplings have been
found to depend on both the alignment of a line connecting the geminal hydrogens
and the nodal plane of the adjacent double bond, and the orientation of
lone-pair electrons on adjacent heteroatoms. Electron withdrawal from symmetrical
bonding orbitals results in more slightly positive geminal coupling constants
while that from antisymmetrical bonding orbitals produces more negative coupling
constants, which has been found to be very large in certain rigid systems.
Department
Chemistry
Collections