84576-38-5Relevant articles and documents
An indenone synthesis involving a new aminotransfer reaction and its application to dibenzopentalene synthesis
Katsumoto, Kenta,Kitamura, Chitoshi,Kawase, Takeshi
, p. 4885 - 4891 (2011/10/31)
o-(Phenylethynyl)phenyllithiums, generated by treatment of o-(phenylethynyl)bromobenzenes with tBuLi, were quenched with N,N-dimethylcarboamides to afford various 2-phenylindenone derivatives in moderate to good yields upon acidic workup. The choice of lithiation reagents was critical. When n-butyllithium was used the yields were reduced. The N-alkyl groups in the carboamides were also important: quenching with N,N-diethylbenzamides also afforded 2,3-diphenylindenones as the sole isolated products, but quenching with N-benzoylpiperidine led to 2-benzoyltolane in good yield. Control experiments revealed that the reactions proceed through a multi-step reaction sequence involving a novel intramolecular transamination to the α-acetylenic carbon of the alkynyl group. The method was applicable to the synthesis of dibenzopentalene derivatives as well as various indenone derivatives. A mechanism for the reaction is discussed.
