A Chiral Cagelike Copper(I) Catalyst for the Highly Enantioselective Synthesis of 1,1-Cyclopropane Diesters
作者:Chao Deng、Li-Jia Wang、Jun Zhu、Yong Tang
DOI:10.1002/anie.201206376
日期:2012.11.12
cyclopropanation of multisubstituted olefins with phenyliodonium ylide malonate has been achieved in the presence of a chiral bisoxazoline copper(I) complex (see scheme). A wide range of substrates undergo the reaction to provide optically active 1,1‐cyclopropane diesters in high yield with up to >99 % ee. A rationale for the enantioselective induction has been proposed.
Asymmetric Cyclopropanation of Alkenes with Dimethyl Diazomalonate Catalyzed by Chiral Diene-Rhodium Complexes
作者:Takahiro Nishimura、Yuko Maeda、Tamio Hayashi
DOI:10.1002/anie.201003775
日期:——
Chiral tridentate ligand: A chiral diene–rhodium complex (1; see scheme) was found to catalyze the intermolecular asymmetric cyclopropanation of alkenes with dimethyldiazomalonate to give 1,1‐cyclopropane diesters in good yields and with high enantioselectivity.
Highly Enantioselective and Diastereoselective Cycloaddition of Cyclopropanes with Nitrones and Its Application in the Kinetic Resolution of 2-Substituted Cyclopropane-1,1-dicarboxylates
作者:Alesandere Ortega、Rubén Manzano、Uxue Uria、Luisa Carrillo、Efraim Reyes、Tomas Tejero、Pedro Merino、Jose L. Vicario
DOI:10.1002/anie.201804614
日期:2018.7.2
Racemic cyclopropyl ketones undergo enantioselectiverearrangement to deliver the corresponding dihydrofurans in the presence of a chiral phosphoric acid as the catalyst. The reaction involves activation of the donor‐acceptor cyclopropane substrate by the chiral Brønsted acid catalyst to promote the ring‐opening event, thus generating a carbocationic intermediate that subsequently undergoes cyclization