Novel Stereoselective Syntheses of Highly Functionalized Benzannulated Pyrrolizidines and Indolizidines by Samarium Diiodide Induced Cyclizations of Indole Derivatives
摘要:
Suitably substituted heteroaromatic compounds such as indole and pyrrole derivatives are excellent acceptor units for intramolecular couplings of samarium ketyls. They furnish highly functionalized indole derivatives with very good diastereoselectivities additionally. Intermediate samarium enolates can be trapped by electrophiles, allowing efficient tandem reactions.
Electroreductive Intramolecular Coupling of 1-Indolealkanones
作者:Naoki Kise、Toshiyuki Mano、Toshihiko Sakurai
DOI:10.1021/ol801876k
日期:2008.10.16
The electroreduction of 1-indolealkanones in isopropanol gave five-, six-, and seven-membered trans-cyclized products stereospecifically. On the other hand, the electroreduction of 3-methoxycarbonyl-1-indolealkanones afforded mixtures of two diastereomers of the corresponding trans- and cis-cyclized products. The DFT calculations for the radical anions support that the reductive couplings of 1-indolealkanones
Here we summarise our results for SmI2-induced 5-exo-trig to 8-exo-trig reductive cyclisations of suitably substituted indole and pyrrole derivatives. All precursors were easily prepared by simple N-alkylation or N-acylation of indole and pyrrole derivatives with the corresponding iodo alkanones, acid chlorides or lactones. The SmI2-induced cyclisations in most cases provided tri- and tetracyclic derivatives
Novel Stereoselective Syntheses of Highly Functionalized Benzannulated Pyrrolizidines and Indolizidines by Samarium Diiodide Induced Cyclizations of Indole Derivatives
作者:Steffen Gross、Hans-Ulrich Reissig
DOI:10.1021/ol0355581
日期:2003.11.1
Suitably substituted heteroaromatic compounds such as indole and pyrrole derivatives are excellent acceptor units for intramolecular couplings of samarium ketyls. They furnish highly functionalized indole derivatives with very good diastereoselectivities additionally. Intermediate samarium enolates can be trapped by electrophiles, allowing efficient tandem reactions.