You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A Coupling of Benzamides and Donor/Acceptor Diazo Compounds To Form γ-Lactams via Rh(III)-Catalyzed C-H Activation. The coupling of O-pivaloyl benzhydroxamic acids with donor/acceptor diazo compounds provides isoindolones in high yield. The reaction tolerates a broad range of benzhydroxamic acids and diazo compounds, including substituted 2,2,2-trifluorodiazoethanes. Mechanistic experiments suggested that C-H activation is turnover-limiting and irreversible and that insertion of the diazo compound favors electron-deficient substrates.
{"Chemical": ["2,2,2-trifluorodiazoethanes", "C-H", "diazo", "Benzamides", "Rh(III)", "benzhydroxamic acids", "\u03b3-Lactams", "Diazo", "O-pivaloyl benzhydroxamic acids", "isoindolones"]}