A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

Molecules

MariaA. Chiacchio¹  Paola Vitale²  Corrado Cuocci³  Roberta Amuso⁴  Bartolo Gabriele⁴  Marzia Petrilli⁴  Lucia Veltri⁴ 

[1] Department of Drug Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari, Italy;Institute of Crystallography, National Research Council, Via Amendola, 122/O, 70126 Bari, Italy;Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, Via Pietro Bucci 12/C, 87036 Arcavacata di Rende, Italy;

关键词: alkynes;    annulation;    benzimidazoxazinones;    heterocycles;    polycyclic heterocycles;    heterocyclization;   

DOI  :  10.3390/molecules26082318

来源: DOAJ

【 摘 要 】

A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl₂-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH₂Cl₂, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be trapped by substrates bearing a nucleophilic group) and activates the triple bond toward intramolecular nucleophilic attack by the carbamate group. The structure of representative products has been confirmed by X-ray diffraction analysis.

【 授权许可】

Unknown