“Cyclopropanation of Cyclopropanes”: GaCl<sub>3</sub>-Mediated Ionic Cyclopropanation of Donor–Acceptor Cyclopropanes with Diazo Esters as a Route to Tetrasubstituted Activated Cyclopropanes
作者:Irina A. Borisova、Daria-Maria V. Ratova、Konstantin V. Potapov、Anna V. Tarasova、Roman A. Novikov、Yury V. Tomilov
DOI:10.1021/acs.joc.0c02983
日期:2021.3.19
A new ionic cyclopropanation process involving the addition of diazo esters to donor–acceptor cyclopropanes (DAC) activated by GaCl3 has been developed. The reactions occur via 1,2-zwitterionic gallium complexes with elimination of nitrogen in all cases to give 1,1,2,3-tetrasubstituted cyclopropanes as the main products. Also, a number of related processes with the formation of various polysubstituted
已经开发出一种新的离子环丙烷化工艺,该工艺涉及将重氮酯添加到由GaCl 3活化的供体-受体环丙烷(DAC)中。该反应通过1,2-两性离子镓络合物进行,在所有情况下都消除了氮,从而得到1,1,2,3-四取代的环丙烷作为主要产物。另外,已经开发了许多与形成各种多取代的环丙烷,烯烃和环丁烷的相关方法,包括多次重氮酯加成的产物。通过开发的方法获得的四取代的环丙烷是活化的环丙烷,例如DAC,并且可以这种能力用于进一步的合成。TiCl 4促进它们与苯甲醛的新反应已经证明并且其涉及另外的官能团之一,其导致五元内酯。详细讨论了发生过程的机理,以及形成的多种产物的结构和立体化学。