Philip Warner

Halo-Enediynes: Probing the Electronic and Stereoelectronic Contributions to the Bergman Cycloaromatization

Efficient routes to three classes of 10-membered oxa-enediynes are presented. The electronic and stereoelectronic contributions to half-lives are supported by density functional theory calculations. One member of this class cyclizes to give an isochroman which binds to and degrades the aryl hydrocarbon receptor (AhR).

Lithium norcaranylidenoids. Alkylation and epimerization

Abstract The epimeric 7-bromo-7-lithionorcaranes have been stereospecifically generated; the exo -bromo isomer is stable at −78°C, while the endo - bromo isomer is reactive. The stereochemistry of its reaction with nBuLi involves inversion.

On carbene alkene complexes

Abstract It is shown that a recent claim for the intermediacy of a carbene alkene complex is unsubstantiated. An alternative mechanism is proposed.

Synthesis and molecular structure of a tetra-t-butylethylene derivative obtained from a propellanic carbenoid. ☆

Abstract The carbonic dimers of some tricyclic cyclopropylidenoids have been isolated. The X-ray structure of one ( 12 ) has been determined. These are derivatives of tetra- t -butylethylene ( 1 ).

Skattebol type rearrangement via α-bromotrimethylstannyl cyclopropane thermolysis: what is the mechanism?

Abstract Solution thermolysis of the epimers 5 gave rise to separate sets of products, including, for one, Skattebol-type rearrangement. However, neither epimer produced a free carbene.

Synthesis of Some 3-Substituted-2,4-dimethyl-1,3-pentadienes1

Abstract Pyrolysis of various l-bromo-2,2,3,3-tetramethylcyclopropanes leads to the corresponding 3-substituted-2,4-dimethylpenta-1,3-dienes in good yield.

Double bridgehead olefins via pyrolysis

Abstract Pyrolysis of diacetate 5 produced 3 major products, 6 – 8 . The most reasonable pathway to these products, supported by deuterium labelling studies, is via double bridgehead olefins and .

On the question of allene formation from tricyclic cyclopropylidenes

Abstract The carbenoid or carbene derived from 8 undergoes dimerization or trapping with DPIBF. The allene mechanism previously proposed was made doubtful by the finding that stereoisomeric carbenes and give stereoisomeric products without crossover.

The effect of Ag(I) ion on product composition in hydrolysis

Abstract The product olefin stereochemistry from the hydrolysis of some cyclopropyl bromides is dependent on [Ag + ].

Conclusive evidence for and stereochemistry of protonation of compounds containing a bridgehead double bond in a seven-membered ring

Die Solvolyse der tricyclischen Dibrom-Verbindung (I) in Gegenwart von Silberperchlorat fuhrt uber diskutierte Zwischenstufen wie (II) und (III) zu den beiden Reaktionsprodukten (IV) und (V); analog erhalt man aus (VI) die Solvolyseprodukte (VII) und (VIII), (VIII) kann zu (V) hydriert werden.