K. N. Houk

TL;DR: It is shown that the limited stability of tetrazines in biological media strongly correlates with the electron-withdrawing effect of the substituent, while intramolecular repulsion increases the reactivity without reducing the stability.

TL;DR: In this paper, the potential role of "H-vinyl" conical intersections in a photochemical process known as the hula twist has been evaluated with complete active space self-consistent field calculations, and proposals about the geometries involved in the Hula-twist mechanism are discussed and contrasted with the conventional one-bond flip mechanism of cis-trans isomerization.

TL;DR: 4,4-Difluoro-4H-pyrazoles are new electron-deficient dienes with rapid reactivities toward strained alkynes, and the computationally predicted rate enhancement from hyperconjugative antiaromaticity induced by fluorination of cyclopentadienes at the 5-position extends to five-membered heterocyclic diene containing a saturated center.

TL;DR: NMR spectra of the free bases and salts of phenyladamantylpiperidine and phenylcyclohexylpipersidine and an X-ray crystal structure of the adamantane derivative verify the preferred conformations of these molecules in solution and the solid state.