Synthesis of isoxazoloazaborines via gold(i)-catalyzed propargyl aza-Claisen rearrangement/borylative cyclization cascade. Issue 12 (19th January 2022)

• Record Type: Journal Article
• Authors: Tsuda, Masato; Morita, Taiki; Nakamura, Hiroyuki
• Is Part Of: Chemical communications. Volume 58:Issue 12(2022)
• Page Start: 1942
• Page End: 1945
• Publication Date: 2022-01-19
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/d1cc07002a
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : Isoxazoloazaborines have been synthesized from 4- N -propargylaminoisoxazole via gold(i )-catalyzed propargyl aza-Claisen rearrangement followed by electrophilic borylative cyclization in 27–86% yields. Abstract : Isoxazoloazaborines 3 and 5 have been synthesized from 4- N -propargylaminoisoxazole 1 via gold(i )-catalyzed propargyl aza-Claisen rearrangement followed by electrophilic borylative cyclization in 27–86% yields. In situ generation of isoxazole 2 having an amino group and allenyl functionality is essential to give highly substituted isoxazoloazaborines 3 and 5, although the conventional propargyl aza-Claisen rearrangement readily affords the corresponding nitrogen-containing heterocycles, such as pyridines and pyrroles. The resulting isoxazoloazaborine 5a underwent the N–O bond insertion of zinc carbenoid to give oxazine-fused azaborine 6 in 48% yield.