在三氟甲磺酸中将1-芳基-4,4,4-三氯丁-2-烯-1-酮环化生成3-三氯甲基茚满-1-酮
Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid.
作者信息
Sokolov Vladislav A, Golushko Andrei A, Boyarskaya Irina A, Vasilyev Aleksander V
机构信息
Department of Organic Chemistry, Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg, 199034, Russia.
Department of Chemistry, Saint Petersburg State Forest Technical University, Institutsky per., 5, Saint Petersburg, 194021, Russia.
出版信息
Beilstein J Org Chem. 2023 Sep 27;19:1460-1470. doi: 10.3762/bjoc.19.105. eCollection 2023.
Trichloromethyl-substituted enones (1-aryl-4,4,4-trichlorobut-2-en-1-ones, ArCOCH=CHCCl, CCl-enones) undergo intramolecular transformation into 3-trichloromethylindan-1-ones (CCl-indanones) in Brønsted superacid CFSOH (triflic acid, TfOH) at 80 °C within 2-10 h in yields up to 92%. Protonation of the carbonyl oxygen of the starting CCl-enones by TfOH affords the key reactive intermediates, the O-protonated forms ArC(=OH)CH=CHCCl, which are then cyclized into the target CCl-indanones. These cations have been studied experimentally by means of NMR spectroscopy in TfOH and theoretically by DFT calculations. Under the same superacidic conditions in TfOH, CCl-hydroxy ketones (1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones; ArCOCHCH(OH)CCl) undergo dehydration to the corresponding CCl-enones, which are further cyclized into CCl-indanones. The yields of CCl-indanones starting from CCl-hydroxy ketones are up to 86% in TfOH at 80 °C within 3-18 h.
三氯甲基取代的烯酮（1-芳基-4,4,4-三氯丁-2-烯-1-酮，ArCOCH=CHCCl，CCl-烯酮）在布朗斯特超强酸CFSOH（三氟甲磺酸，TfOH）中于80°C下2至10小时内发生分子内转化生成3-三氯甲基茚满-1-酮（CCl-茚满酮），产率高达92%。起始CCl-烯酮的羰基氧被TfOH质子化得到关键的反应中间体，即O-质子化形式ArC(=OH)CH=CHCCl，然后它们环化生成目标CCl-茚满酮。这些阳离子已通过在TfOH中的NMR光谱实验研究，并通过DFT计算进行了理论研究。在TfOH中相同的超强酸性条件下，CCl-羟基酮（1-芳基-4,4,4-三氯-3-羟基丁-1-酮；ArCOCHCH(OH)CCl）脱水生成相应的CCl-烯酮，后者进一步环化生成CCl-茚满酮。在TfOH中于80°C下3至18小时内，以CCl-羟基酮为起始原料生成CCl-茚满酮的产率高达86%。
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