Resonance energies of vinylcarbenes.

The stabilization energy provided by resonance in singlet and triplet vinylcarbenes is evaluated using density functional and G3 theory, without symmetry restriction. Structural and charge change upon rotation are reviewed with singlet vinylcarbene exhibiting a larger barrier (1s-TS-1s-E), 5.49 (7.

Neutral homoaromaticity in some heterocyclic systems.

[reaction: see text] Neutral homoaromaticity has been evaluated in heterocyclic systems related to the bicyclo[3.2.1]octane skeleton with replacement of CH(2) at C-2 in bicyclo[3.

A study into the possible homoaromatic nature of some related carbene and cationic intermediates with the potential for transannular interaction.

A comparison of the aromatic nature of the cations and carbenes centered at the 8-position of tricyclo[3.2.1.

The nature and role of 8-deltacyclyl and 7-isodeltacyclyl cations in solvolytic reactions of parent brosylates.

Solvolysis of exo-8-deltacyclyl brosylate proceeds directly through a C(2) delocalized cation to exo-8-deltacyclyl acetate. The solvolysis of the endo epimer presents a more complex picture, reacting via a classical deltacyclyl cation, the nonclassical C(2) delocalized cation, and the isodeltacyclyl cation. The solvolysis of exo-7-isodeltacyclyl brosylate generates the 7-isodeltacyclyl ion and subsequently the C(2) delocalized deltacyclyl cation forming 8-deltacyclyl acetate and exo-7-isodeltacyclyl acetate.