Dibenzothiophenes and related compounds. V. Reactions of 5-substituted dibenzothiophenium salts with organometallic reagents.
作者:MIKIO HORI、TADASHI KATAOKA、HIROSHI SHIMIZU、MICHIHIRO MIYAGAKI
DOI:10.1248/cpb.22.2020
日期:——
In order to compare the mechanisms of reactions of sulfonium salts with organolithiums and Grignard reagents, the reactions between 5-substituted dibenzothiophenium salts and methyllithium, methylmagnesium halides, and phenylmagnesium halides have been investigated to get a large difference as shown in Tables I and II, respectively. The reactions of 5-substituted dibenzothiophenium salts with methyllithium gave ring-opening products (I) as main products in Table I, whereas the reactions of those with methylmagnesium iodide gave no I or only little. Instead, these reactions gave ringopening products (III) as main products in Table II. The mechanisms of the formation of the products of the runs in Table I and II have been explained as shown in Chart 2 and Chart 4, respectively.
为了比较锍盐与有机锂和格氏试剂的反应机理,研究了 5-取代二苯并噻吩盐与甲基锂、甲基卤化镁和苯基卤化镁的反应,结果差异很大,分别如表 I 和表 II 所示。在表 I 中,5-取代二苯并噻吩盐与甲基锂的反应以开环产物(I)为主要产物,而与甲基碘化镁的反应则没有或只有少量的开环产物(I)。相反,这些反应产生的开环产物(III)是表 II 中的主要产物。表 I 和表 II 中运行产物的形成机理分别如图 2 和图 4 所示。