4-Unsubstituted 2-azetidinones 3a,b, which are useful intermediates for the synthesis of carbapenem antibiotics, have been enantiospecifically and diastereoselectively prepared starting from asymmetrized bis(hydroxymethyl)acetaldehyde (BHYMA*)4, a new chiral building block obtained through biological methods. The key steps are the highly diastereoselective addition of Me2CuLi to 4 (diast. ratio = 95
从合成的不对称双(羟甲基)
乙醛(BHYMA *)4对映体和非对映选择性地制备了4-非取代的
2-氮杂环丁酮3a,b,它们是合成碳青霉烯抗生素的有用中间体,是一种通过
生物方法获得的新手性结构单元。关键步骤是将Me 2 CuLi高度非对映选择性地添加到4中(最小比率= 95:5),以及在存在(t Pr)3 Si醚的情况下,通过使用a进行t BuMe 2 Si醚的区域选择性解封闭。新颖的方法。