Adding an aryne to a tertiary allylamine affords o-allylaniline products of an aza-Claisen rearrangement. The aryne simultaneously provides the pi component for the rearrangement and the quaternization event that lowers the activation energy for the sigmatropic shift. The reaction was applied to the synthesis of medium-ring benzannulated amines (see scheme).

ortho C-H activation of benzoic acids with Pd(II) generates an oxapalladacycle that can decarboxylate to produce a palladium-associated aryne. The arynes then undergo [2+2+2] trimerisation to afford triphenylenes.

A fast and efficient nickel-catalysed iodination reaction of aryl and heteroaryl bromides has been developed. The transformation was found to be general for a wide range of substrates and was used for the synthesis of iodo-PK11195, an imaging agent of Alzheimer's disease and iniparib, a compound used in the treatment of breast cancer.

Rapid and efficient radioiodination of aryl and heteroaryl bromides has been achieved using a nickel(0)-mediated halogen-exchange reaction. This transformation gives direct access to [(123)I]- and [(125)I]-imaging agents for single photon emission computed tomography (SPECT), such as 5-[(123)I]-A85380 (see scheme, Boc = tert-butyloxycarbonyl, cod = 1,5-cyclooctadiene, TFA = trifluoroacetic acid).

A base-mediated 6-endo-trig cyclization of readily accessible enone-derived α-amino acids has been developed for the direct synthesis of novel 2,6-cis-6substituted-4-oxo-L-pipecolic acids. A range of aliphatic and aryl side chains were tolerated by this mild procedure to give the target compounds in good overall yields. Molecular modeling of the 6-endo-trig cyclization allowed some insight as to how these compounds were formed, with the enolate intermediate generated via an equilibrium process, followed by irreversible tautomerization/neutralization providing the driving force for product formation. Stereoselective reduction and deprotection of the resulting 2,6-cis-6-substituted 4-oxo-L-pipecolic acids to the corresponding 4-hydroxy-L-pipecolic acids was also performed.

Ein Arin und ein tertiäres Allylamin liefern durch eine Aza‐Claisen‐Umlagerung o‐Allylanilinprodukte. Das Arin bietet sowohl die π‐Komponente für die Umlagerung als auch die Quaternisierung, die die Aktivierungsenergie der sigmatropen Verschiebung senkt. Die Reaktion wurde zur Synthese benzanellierter cyclischer Amine mit mittlerer Ringgröße genutzt (siehe Schema).magnified image

No abstract

Eine schnelle und effiziente Radioiodierung von Aryl‐ und Heteroarylbromiden gelingt mit einer Nickel(0)‐katalysierten Halogen‐Austauschreaktion. Diese Umsetzung ermöglicht den direkten Zugang zu [123I]‐ und [125I]‐Imaging‐Substanzen für Einzelphotonen‐Emissions‐Computertomographie (SPECT), wie z. B. 5‐[123I]‐A85380 (siehe Schema, Boc=tert‐Butyloxycarbonyl, cod=1,5‐Cyclooctadien, TFA=Trifluoressigsäure).