Reactions of diazo esters with electron-deficient alkenes in the presence of Lewis acids
作者:R. A. Novikov、D. N. Platonov、V. A. Dokichev、Yu. V. Tomilov、O. M. Nefedov
DOI:10.1007/s11172-010-0194-0
日期:2010.5
Abstract1,3-Dipolar cycloaddition reaction of diazo esters to electron-deficient dipolarophiles to yield the corresponding 1- or 2-pyrazolines was found to be significantly accelerated with Lewisacids (Yb(OTf)3, Sc(OTf)3, GaCl3, EtAlCl2). The use of GaCl3 as the catalyst leads to the acceleration not only of the 1,3-dipolar cycloaddition reaction, but also subsequent insertion of the CHCO2Me electrophilic
Lewis acid-mediated reactions of donor-acceptor cyclopropanes with diazo esters
作者:R. A. Novikov、D. D. Borisov、Yu. V. Tomilov
DOI:10.1007/s11172-018-2069-8
日期:2018.2
tatives of donor-acceptor cyclopropanes (DACs), mediated by Sc(OTf)3, SnCl4, and GaCl3 proceeded with nitrogen elimination to give the C—C coupling products. No products of the formal [3+3] cycloaddition of diazo compounds to DACs were formed but the main reaction direction was addition of diazo ester to either 1,3- or 1,2-zwitterions generated upon Lewis acid-mediated cyclopropane ring opening giving rise
Dibutyl telluride assists cyclopropanation of α,β-unsaturated ketone, ester, and nitrile with dibromomalonic esters without solvent at room temperature. In addition, it effects alkylidenation of aldehydes including α,β-unsaturated aldehyde with the same reagent.