Photochemical ?-Cleavage of ?, ?-Unsaturated Aryl Ketones: Competition between recombination/disproportionation and dissociation in geminate singlet and triplet radical pairs
the triplet state; (2): that recombination and disproportionation reactions within the geminate singlet and triplet aroyl/allyl radical pairs (11) compete with the dissociation into free radicals (12): (3): that ketone isomerization by paths not involving polarizable radical intermediates is unimportant; (4): that no triplet oxa-di-π-methane type rearrangement products are formed.
[3+2] Cycloaddition Reaction of Cyclopropyl Ketones with Alkynes Catalyzed by Nickel/Dimethylaluminum Chloride
作者:Takashi Tamaki、Masato Ohashi、Sensuke Ogoshi
DOI:10.1002/anie.201106174
日期:2011.12.9
[3+2] cycloaddition between the title compounds gives cyclopentene derivatives in the presence of Me2AlCl. The organoaluminum reagent activates the carbonylgroup of the cyclopropyl ketone through coordination of the oxygen atom to the aluminum, and stabilizes the reaction intermediate by the coordination of the chloride to nickel. cod=1,5‐cyclooctadiene, THF=tetrahydrofuran.