Peptide Chemistry Research Center, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran 19697, Iran.
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
J Org Chem. 2021 Oct 1;86(19):13693-13701. doi: 10.1021/acs.joc.1c01789. Epub 2021 Sep 16.
A transition-metal-free postmodification of the Groebke-Blackburn-Bienaymé (GBB) reaction for the synthesis of spiro[chromene-imidazo[1,2-]pyridin]-3'-imine was discovered. The unusual transformation represents the first example of activation and the reaction of the imidazole carbon atom. In this postcondensational modification, KO-Bu acts as a base, which, after the isomerization of an alkyne moiety to allene, causes the next unique nucleophilic reaction of the imidazole carbon atom that results in spirocyclic structures. The proposed reaction mechanism was confirmed based on the DFT calculations.
发现了一种无过渡金属的 Groebke-Blackburn-Bienaymé（GBB）反应后修饰反应，用于合成螺[色烯-咪唑并[1,2-a]吡啶]-3'-亚胺。这种不寻常的转化代表了对咪唑碳原子的活化和反应的首例实例。在这种后缩合修饰中，KO-Bu 充当碱，在炔烃部分异构化为丙二烯后，引发咪唑碳原子的下一个独特的亲核反应，生成螺环结构。基于 DFT 计算，证实了所提出的反应机制。
