Regioselective synthesis of 4- and 5-oxazole-phosphine oxides and -phosphonates from 2H-azirines and acyl chlorides
作者:Francisco Palacios、Ana M. Ochoa de Retana、José I. Gil、José M. Alonso
DOI:10.1016/j.tet.2004.07.013
日期:2004.9
A simple and efficient regioselective synthesis of 4-oxazole-phosphine oxides 11 and -phosphonates 12 from 2H-azirine-phosphine oxides 1 and -phosphonates 6 is described. The key step for the synthesis of oxazoles 11 is a base-mediated ring closure of vinylogous α-aminophosphorus compounds derived from phosphine oxides 4 and from phosphonates 8. These derivatives 4 and 8 are obtained by reaction of
描述了由2 H-叠氮基膦氧化物1和-膦酸酯6简单和有效的区域选择性合成4-恶唑-膦氧化物11和-膦酸酯12。合成恶唑11的关键步骤是衍生自氧化膦4和膦酸酯8的乙烯基α-氨基磷化合物的碱介导的闭环。这些衍生物4和8是通过官能化的叠氮基1和6与酰氯2的反应以及随后酸催化的开环反应而获得的。N-酰基氮丙啶膦氧化物3和膦酸酯7。N-酰基氮杂吡啶膦氧化物3的区域选择性热环裂解导致α-氯代-β-(N-酰基酰胺基)膦氧化物13,并用碱处理得到5-恶唑膦氧化物16。