[formula: see text] 1,10-Phenanthroline undergoes coupling with ketones promoted by samarium diiodide to produce 2-(1-hydroxyalkyl)-1,10-phenanthrolines. O-Methylation of these derivatives provides the corresponding 2-(1-methoxyalkyl)phenanthrolines. Demethoxylation with samarium diiodide then affords 2-alkylphenanthrolines. This process may be repeated to obtain 2,9-disubstituted phenanthrolines. A variety of new, substituted phenanthrolines are thus obtained. These compounds have numerous potential applications as ligands in metal-promoted reactions, including asymmetric catalysis.
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http://dx.doi.org/10.1021/ol990284w | DOI Listing |
J Org Chem
December 2024
Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
The first deoxygenative hydrosilylation of ketones promoted by samarium diiodide and samarium has been reported. In this approach, secondary alkyl silanes are synthesized from unactivated ketones and chlorosilanes in one step. The carbonyl group of ketones is activated by SmI-mediated single-electron transfer process, which follows a deoxygenative elimination of O=Sm.
View Article and Find Full Text PDFOrg Biomol Chem
October 2024
Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
A direct deoxygenative hydroborylation of ketones with hydroborane ester promoted by a combination of samarium diiodide, samarium and nickel has been developed. In this method, secondary alkyl borate esters are synthesized from unactivated ketones with hydroborane esters in one step. A broad substrate scope and excellent selectivity toward CO cleavage has been demonstrated.
View Article and Find Full Text PDFScience
August 2024
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
Samarium diiodide (SmI) is a privileged, single-electron reductant deployed in diverse synthetic settings. However, generalizable methods for catalytic turnover remain elusive because of the well-known challenge associated with cleaving strong Sm-O bonds. Prior efforts have focused on the use of highly reactive oxophiles to enable catalyst turnover.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
April 2024
Graduate School of Pharmaceutical Sciences, The University of Tokyo.
Batrachotoxin (1) is a potent cardio- and neurotoxic steroid isolated from certain species of frogs, birds, and beetles. We previously disclosed two synthetic routes to 1. During our synthetic studies toward 1, we explored an alternative strategy for efficiently assembling its 6/6/6/5-membered steroidal skeleton (ABCD-ring).
View Article and Find Full Text PDFChemistry
May 2024
Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany.
This study analyzes the samarium diiodide-promoted cyclizations of 5-arylpentan-2-ones to dearomatized bicyclic products utilizing density functional theory. The reaction involves a single electron transfer to the carbonyl group, which occurs synchronously with the rate determining cyclization event, and a second subsequent proton-coupled electron transfer. These redox reactions are accurately computed employing small core pseudo potentials explicitly involving all f-electrons of samarium.
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