Laboratório de Síntese, Reatividade, Avaliação Farmacológica e Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria-Rio Grande do Sul, 97105-900 Brazil.
J Org Chem. 2013 Feb 15;78(4):1630-7. doi: 10.1021/jo302770g. Epub 2013 Feb 7.
This report describes the synthesis of 4-organoselenylisoxazoles via FeCl(3)/RSeSeR-mediated intramolecular cyclization of alkynone O-methyloximes. The optimized conditions allowed the cyclization to proceed at room temperature under ambient atmosphere, and the reaction requires a short time to be completed. The reaction conditions tolerated neutral, electron-donating and electron-withdrawing groups present in both substrates, alkynone O-methyloximes and diorganyl diselenides. Treatment of 4-organoselenylisoxazoles with n-butyllithium, followed by trapping with electrophiles, furnished the functionalized isoxazoles in good yields. The obtained products also proved to be suitable substrates for the preparation of 4-bromoisoxazoles via Br/Se exchange reaction.
本报告描述了通过 FeCl(3)/RSeSeR 介导的炔酮 O-甲氧基肟的分子内环化反应合成 4-有机硒唑。优化条件允许在室温下、在环境气氛中进行环化反应，并且反应在短时间内完成。反应条件耐受底物中的中性、给电子和吸电子基团，即炔酮 O-甲氧基肟和二芳基二硒醚。用正丁基锂处理 4-有机硒唑，然后用亲电试剂捕获，以良好的收率得到功能化的异恶唑。通过 Br/Se 交换反应获得的产物也被证明是制备 4-溴异恶唑的合适底物。
