In 2022,Jiang, Ben-Jie; Zhang, Song-Lin published an article in Advanced Synthesis & Catalysis. The title of the article was 《Synthesis of Quinolines and 2-Functionalized Quinolines by Difluorocarbene Incorporation》.Computed Properties of C20H20BrP The author mentioned the following in the article:
A general method was developed to allow de novo construction of quinolines I [R = Me, cyclopropyl, Ph, etc.] and C2-functionalized quinolines II [R1 = Me, cyclopentyl, Ph; R2 = Ph, Bn, 1-naphthyl, etc.; R3 = H, Me] from ortho-alkenyl anilines in the presence of a difluorocarbene precursor. This method exploited a crucial reactivity of in-situ generation of isocyanides from condensation of primary aniline with difluorocarbene. Subsequent α-addition of isocyanide by neighboring alkenyl group constructs the quinoline ring. Furthermore, when a combination of difluorocarbene precursor and Se are present, selenoisocyanate intermediates were tentatively generated that upon nucleophilic addition by ortho-alkenyl produce 2-SeH quinolines. In the presence of a second nucleophile such as anilines, competing nucleophilic addition of anilines to the selenoisocyanate was preferred, generating selenourea intermediate. Further nucleophilic addition of the ortho-alkenyl to selenourea followed by elimination of H2Se produces 2-aminoquinolines. This allows one-step multi-component modular preparation of various C2-functionalized quinolines from readily available starting compounds This method showed good yields, scope and chemoselectivity. It was operationally convenient and friendly without manipulating unpleasant isocyanides. The difluorocarbene-enabled primary amine to isocyanide conversion may be exploited to develop other interesting reactions. In the experiment, the researchers used Ethyltriphenylphosphonium bromide(cas: 1530-32-1Computed Properties of C20H20BrP)
Ethyltriphenylphosphonium bromide(cas: 1530-32-1) is a phase transfer catalyst, used to accelerate the cure of phenolic-based epoxy resins, certain fluoroelastomer resins and thermosetting powder coatings. CatOnium ETPB is also used as catalysts in the synthesis of certain organic compounds.Computed Properties of C20H20BrP
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary