A short formal synthesis of (−)-methylenolactocin via a nickel catalyzed intramolecular carbozincation
作者:Andrea Vaupel、Paul Knochel
DOI:10.1016/0040-4039(94)02243-5
日期:1995.1
The lactone 2 which can be converted in one step into (−)-methylenolactocin 1 was prepared in 4 steps, 30 % overall yield and > 92 % ee starting from (E)-3-trimethylsilylpropenal 4. The key step is a new nickel catalyzed cyclization of the polyfunctional bromo-alkenylsilane 3 mediated by Et2Zn. The intermediate organozinc species 7 has been directly oxidized to an aldehyde with oxygen.
内酯2( - ) -可被转化在一个步骤中进methylenolactocin 1在4个步骤制备,30%总产率和> 92%ee的由(E)起始-3- trimethylsilylpropenal 4。关键步骤是由Et 2 Zn介导的多官能溴-链烯基硅烷3的新的镍催化环化反应。中间有机锌物质7已被氧气直接氧化为醛。