A New and Convenient Synthesis of 1,2-Dioxobenzocyclobutene via Photodecarbonylation

Synthesis, Characterization, and Some Reactions of the Tricarbonylchromium Complexes of 1,3-Indandione and Ninhydrin

“…Due to the electron withdrawal of the tricarbonylchromium group the regioselectivity of the reaction did not neccessarily have to be the same as in the reaction of uncomplexed indantrione (19): The benzylic keto A similar result was obtained upon treatment of ninhydrin complex 8 with 1-methoxy-3-trimethylsiloxy-1,3-butagroups are more electrophilic than in the ligand, and the difference in electrophilicity between them and C-2 de-diene (47, Danishefsky diene [45] ). Complex rac-48 was obtained as an orange-red solid in 78% yield (de > 95%, 1 H creases. Finally, we wanted to verify the suggestion that the diene would diastereoselectively attack the heterodienophile NMR, 13 C NMR) as a result of a hetero-DielsϪAlder Figure 3) were obtained from dichloromethane/petro-ies were determined with APT and DEPT techniques.…”

“…If similar chemistry were possible with these comavailable by an improved synthesis. [1] The most striking ob-plexes, this would pave a way to benz-anellated cyclononservation in this context was the dianionic oxy-Cope re-anedione and hydrindane systems. The keto functionalities arrangement upon diaddition of vinyllithium to 2, which in complexes 5Ϫ8 should be rather electrophilic, because, resulted in the formation of benzocyclooctenedione com-as in 2, the sp 2 hybridization of the benzylic carbon atoms plex 3 in high yield under mild reaction conditions.…”

“…Although complexation of 18 was unsuccessful, the compound came out to be a valuable starting material for a new synthesis of benzocyclobutenedione by photodecarbonylation and subsequent deacetalization. [1] While the acetalization under standard conditions took place only at the keto groups adjacent to the aromatic ring, As with benzocyclobutenedione, all attempts to directly selective acetalization was possible at C-2 using 2-bromocoordinate the ligands by treatment of indantrione (19) or ethanol/potassium carbonate. [9] Starting from ninhydrin ninhydrin (17) with hexacarbonylchromium or triammine-(17) or indantrione (19) the sequence of acetalization reactricarbonylchromium were not successful and resulted in tions is interchangeable, so that either 18 or 20 are interdecomposed material only.…”

A New Oxocarbon C12O6 via Highly Strained Benzyne Intermediates

“…The cycloadduct is hydrolyzed to form 2 , which can be dibrominated at C‐2 with N ‐bromosuccinimide to give 3 after hydrolysis 12. 13 Alternatively, 3 can be obtained by photodecarbonylation of 1,3‐bis(ethylenedioxy)indan‐2‐one followed by hydrolysis of the acetal groups 14…”

Synthese des Kohlenstoffoxids C12O6 über hoch gespannte Benz‐ine

“…[12,13] Alternativ ist 3 durch eine Photodecarbonylierung von 1,3-Bis(ethylendioxy)indan-2-on und nachfolgende Acetal-Hydrolyse erhältlich. [14] Suzuki et al haben den Zugang zu einer Vielzahl von Derivaten des Benzocyclobutens entscheidend verbessert, indem sie den Iod-Lithium-Austausch in ortho-Iodtriflaten wie 4 nutzten. Nachfolgende Triflat-Eliminierung führt zum entsprechenden Benz-in.…”