Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• Xing Liu Wenjing Shi Jing Sun Chao-Guo Yan College of Chemistry & Chemical Engineering, Yangzhou University, Jiangsu, Yangzhou 225002, China 10.3762/bjoc.19.143 Abstract A straightforward synthetic protocol for the efficient construction of diazepine-containing spiroindolines has been developed

• expected spiro product 7c was successfully obtained in 70% yield, which clearly demonstrated that this base-promoted annulation reaction is applicable for the large-scale synthesis of diazepine-containing spiroindolines. Conclusion In summary, we have developed a synthetic protocol for the base-mediated

Post-Ugi gold-catalyzed diastereoselective domino cyclization for the synthesis of diversely substituted spiroindolines

• Amit Kumar,
• Dipak D. Vachhani,
• Sachin G. Modha,
• Sunil K. Sharma,
• Virinder S. Parmar and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2013, 9, 2097–2102, doi:10.3762/bjoc.9.246

• adducts which are subjected to a cationic gold-catalyzed diastereoselective domino cyclization to furnish diversely substituted spiroindolines. All the reactions run via an exo-dig attack in the hydroarylation step followed by an intramolecular diastereoselective trapping of the imminium ion. The whole

• sequence is atom economic and the application of a multicomponent reaction assures diversity. Keywords: alkynes; gold; indoles; multicomponent; spiroindolines; Ugi; Introduction The importance of nitrogen containing heterocyclic molecules in chemical biology is undisputed. The synthesis of such

• ][39][40][41][42][43]. We have recently reported a post-Ugi gold-catalyzed intramolecular domino cyclization sequence which produces spiroindolines (Scheme 1) [44]. The first step in this sequence is an Ugi four-component reaction (Ugi-4CR) [4][5] with 2-alkynoic acid as an alkyne source. The second