2370-96-9Relevant academic research and scientific papers
Photolysis of indan-l,2-dione derivatives in oxygen-doped argon matrix at low temperature
Itoh, Takayoshi,Tatsugi, Jiro,Tomioka, Hideo
, p. 475 - 481 (2009)
Photolysis of indan-l,2,3-trion (la), benzo[ft]furan-2,3-dione (lb), and N-methylisatin (1c) in argon matrix either with or without oxygen at 10 K was investigated by IR spectroscopy in combination with DFT calculations. The results indicate that while 1a and 1b gave the products mixture as a result of α-cleavage, followed by decarbonylation, 1c was rather photostable under similar conditions. However, when the irradiation was carried out in argon matrix doped with 20% oxygen, 1c decomposed much more efficiently than that in argon matrix and cyclic diacyl peroxide presumably formed by trapping of initial diradical originating from α-cleavage by molecular oxygen was detected. Similar irradiation of 1b also gave cyclic diacyl peroxide along with photodecarbonylation products, but irradiation of 1a in oxygen-doped matrix produced not only cyclic diacyl peroxide but also products as a result of oxidation of photodecarbonylation product. The present observation reveals that photolysis of ketones in oxygen-doped matrix at low temperature provides useful information concerning the reactivities of ketones toward α-cleavage.
Ketene-Ketene interconversion. 6-Carbonylcyclohexa-2,4-dienone-hepta-1,2,4, 6-tetraene-1,7-dione-6-oxocyclohexa-2,4-dienylidene and wolff rearrangement to fulven-6-one
Koch, Rainer,Blanch, Rodney J.,Wentrup, Curt
, p. 6978 - 6986 (2014/08/18)
6-Carbonylcyclohexa-2,4-dienone (1) has been generated by flash vacuum thermolysis (FVT) with Ar-matrix isolation of methyl salicylate (7), 2-phenylbenzo-1,3-dioxan-4-one (8), phthalic peranhydride (9), and benzofuran-2,3-dione (11) and also by matrix photolysis of 9, 11, and 2-diazocyclohepta-4,6-dien-1,3-dione (12). In each case, FVT above 600 °C results in decarbonylation of 1 and Wolff rearrangement to fulven-6-one (13) either concertedly or via open-shell singlet 6-oxocyclohexa-2,4-dienylidene (18). Ketenes 1 and 13 were characterized by IR spectroscopy. Photolysis of matrix-isolated 1 at 254 nm also results in the slow formation of 13. The sequential formation of ketenes 1 and 13 from 7 has also been monitored by FVT-mass spectrometry, and 13 has been trapped with MeOH to afford methyl 1,3-cyclopentadiene-1- and -2-carboxylates 15 and 16. FVT of methyl salicylate-1-13C 7a revealed a deep-seated rearrangement of the 13C-labeled 1a to hepta-1,2,4,6-tetraen-1,7-dione (17a) by means of electrocyclic ring opening followed by a facile 1,5-H shift and recyclization prior to CO-elimination and ring contraction to 13C-labeled 13. The rearrangement mechanism is supported by M06-2X/6-311++G(d,p) calculations, which predict feasible barriers for the FVT rearrangements and confirm the observed labeling pattern in the isolated methyl salicylate 7a/7b and methyl cyclopentadienecarboxylates 20 and 21 resulting from trapping of 13 with MeOH.
