Treatment of a benzene or a CH2Cl2 solution of bis(N,N-dimethylcarbamoylseleno)methanes with SnCl4 afforded β-1,3,5-triselenanes, and the key intermediates, acylselonium ions and selenoaldehydes, were successfully trapped by using allyltrimethylsilane or 2,3-dimethyl-1,3-butadiene to obtain the allylation products or the cycloadducts, respectively.
A Preparation of Alkyl or Alkenyl<i>N</i>,<i>N</i>-Dimethylchalcogenocarbamates and Their One-Step Conversion into Symmetrical Dialkyl or Dialkenyl Dichalcogenides
Alkyl or alkenyl N,N-dimethylchalcogenocarbamates were easily prepared by a stepwise treatment of bis(N,N-dimethylcarbamoyl) dichalcogenides with NaH or NaBH4, followed by various alkylating agents or acetylenes bearing electron-withdrawing substituents. The one-step conversion of alkyl or alkenyl N,N-dimethylselenocarbamates or N,N-dimethyltellurocarbamates into the corresponding symmetrical dialkyl or dialkenyl dichalcogenides was also achieved efficiently by treating with SnCl4.
先用 NaH 或 NaBH4 分步处理双(N,N-二甲基氨基甲酰基)二羰基化合物,再用各种烷基化剂或带有抽电子取代基的乙炔基,就能轻松制备出烷基或烯基 N,N-二甲基羰基氨基甲酸盐。用 SnCl4 处理烷基或烯基 N,N-二甲基硒羰基氨基甲酸酯或 N,N-二甲基碲羰基氨基甲酸酯,也能一步高效地转化为相应的对称二烷基或二烯基二羰基化合物。
Synthesis of Isochalcogenazole Rings by Treating β-(<i>N</i>,<i>N</i>-Dimethylcarbamoylchalcogenenyl)alkenyl Ketones with Hydroxylamine-<i>O</i>-sulfonic Acid
β-(N,N-Dimethylcarbamoylselenenyl)- and β-(N,N-dimethylcarbamoyltellurenyl)alkenyl ketones were converted into isoselenazoles and isotellurazole Te-oxides, respectively, simply by treating with hydroxylamine-O-sulfonic acid, and deoxygenation of the latter products was successfully carried out by treating with PPh3. Alternative treatment of ynone oxime tosylates with hydrochalcogenide ions or N,N-dimethylchalcogenocarbamate ions also gave the same isochalcogenazole rings. These reactions were assumed to proceed through intramolecular nucleophilic substitution on the nitrogen atom of oxime sulfonates by the attack of in situ generated chalcogen nucleophiles.