Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform

Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform

Synthetic Methods Part(I) Free-Radical Reactions

No description supplie

Photosolvolysis reactions of 3-alkoxypyridinium tetraflouroborate salts

Irradiation of a series of 3-alkoxypyridinium tetrafluoroborate salts in alcohol solution resulted in the formation of cyclopentenone ketals by diastereoselective incorporation of the alcohol solvent under the basic conditions of the photolysis reaction. In a second series of photochemical reactions, the same 3-alkoxypyridinium salts were irradiated in water to yield β-hydroxycyclopentanones stereoselectively

Oxidative rearrangements of bicyclic 2-alkenyl aziridines

Oxidation of a range of photochemically generated aziridines gave products arising from a [2,3] Meisenheimer rearrangement of the initial N-oxide, followed by further oxidation to give delta-hydroxynitrones

The stereoselective addition of organocuprates to cyclopentenyl aziridine derivatives

Various organocopper reagents were added in the expected anti-S(N)2' fashion to cyclopentenyl aziridines, which were derived from the photosolvolysis of pyridinium salts

Investigating the Photochemical Properties of an Arenyl Dienol

Upon irradiation with UV light, an arenyl dienol was transformed into linear and angular <i>meta</i> photocycloadducts and <i>ortho</i> derived photoadducts. Extended exposure to UV radiation resulted in the formation of other degradation products, which shed light on the chemical processes taking place. One of the linear <i>meta</i> photocycloadducts was thermally unstable and underwent further thermal and photochemical transformation, while the <i>ortho</i>-derived photocycloadducts ring-opened and eliminated methanol to afford a cyclooctadienone product

A Photochemical Approach to the Gelsemine Skeleton

A silicon-tethered intramolecular meta photocycloaddition reaction was utilized to prepare a photoadduct, which was subsequently fragmented using m-CPBA to give a model for the skeleton of the alkaloid gelsemine

A palladium-assisted ring annulation for the synthesis of the batrachotoxin ring system

A method for the synthesis of the steroidal nucleus in general and in particular for the cardiotoxin batrachotoxin has been carried out using a 'one-pot' palladium-mediated annulation sequence. © Georg Thieme Verlag Stuttgart