BBAH Primer

The Bent Bond/Antiperiplanar Hypothesis (aka BBAH) is a conceptually novel orbital model for rationalizing the conformation and stereochemical reactivity of organic molecules containing various types of unsaturation. The BBAH is based on the Slater-Pauling bent […]


BBAH paper #8

Thermal Rearrangement of Optically Active Tetradeuterated-2-methoxymethyl-methylenecyclopropane and the Bent Bond/Antiperiplanar Hypothesis The thermolysis of an optically active tetradeuterated 2-methoxymethyl methylenecyclopropane produces a specific ratio of eight possible rearrangement stereoisomers. Despite numerous efforts, this reaction and […]


BBAH paper #7

Bent Bonds and the Antiperiplanar Hypothesis. A Model to Account for Sigmatropic [1,n]-Hydrogen Shifts Sigmatropic hydrogen shifts are rationalized using the BBAH involving antiperiplanar displacement of radical intermediates. The stereochemistry of both thermal and photochemical […]


BBAH paper #6

High Temperature Isomerization of Benzenoid Polycyclic Aromatic Hydrocarbons. An Analysis through the Bent Bond and Antiperiplanar Hypothesis Orbital Model. The properties and stereochemical reactivity of cyclobutadiene, benzene, cyclooctatetraene and the [10]- to [14]annulenes can be […]


BBAH paper #5

Bent Bonds (τ) and the Antiperiplanar Hypothesis – the Chemistry of Cyclooctatetraene and other C8H8Isomers The fascinating chemistry of cyclooctatraene, including its propensity for ring inversion, bond shifting, and valence isomerization, is analyzed by the […]

Chemical Education

Organic Chemistry: Mechanistic patterns

The new textbook “Organic Chemistry: Mechanistic Patterns” by Ogilvie, Ackroyd, Browning, Deslongchamps, Lee, Sauer, 1st Ed., Nelson Education, 2017 has been published (ISBN 017650026-X). Organic ChemWare, a collection of 235 HTML5-compliant interactive animations is integrated […]


BBAH paper #4

Bent Bonds and the Antiperiplanar Hypothesis and the Reactivity at the Anomeric Center in Pyranosides A solo contribution from the P. Deslongchamps group. The stereoselectivity of nucleophilic addition on oxocarbenium ions derived from the bicyclic […]


BBAH paper #3

Bent Bonds and the Antiperiplanar Hypothesis – A Simple Model to Rationalize [1,3]-Sigmatropic Alkyl Shifts The bent bond/antiperiplanar (BBA) hypothesis has been applied to the analysis of [1,3]-sigmatropic alkyl shifts. These thermal rearrangements, for which […]


BBAH paper #2

Bent Bonds and the Antiperiplanar Hypothesis as a Simple Model to Predict Diels-Alder Reactivity: Retrospective or Perspective? “Bent bonds paper #2” appears as Perspectives article in Tetrahedron and makes the cover: G.Deslongchamps, P. Deslongchamps, Bent Bonds and the Antiperiplanar Hypothesis as […]


BBAH paper #1

Bent Bonds, the Antiperiplanar Hypothesis and the Theory of Resonance. A Simple Model to Understand Reactivity in Organic Chemistry The paper that started it all. By taking into consideration bent bonds (τ-bonds, tau-bonds), the antiperiplanar […]