16261-31-7Relevant academic research and scientific papers
Synthesis of Tetrahydroisoquinolines by Visible-Light-Mediated 6- exo -trig Cyclization of α-Aminoalkyl Radicals
Bach, Thorsten,Grübel, Michael,Jandl, Christian
, p. 1825 - 1829 (2019/09/09)
Starting from the respective tertiary α-silylmethyl amines, the intramolecular cyclization of α-aminoalkyl radicals to Michael acceptors produced tetrahydroisoquinolines. The reaction conditions included the use of 5 molpercent of an iridium photoredox catalyst, dimethylformamide as the solvent, and equimolar amounts of water and cesium carbonate as the additives. 13 substrates were synthesized from ortho -alkylbenzaldehydes in a three-step procedure involving a carbonyl condensation, a radical bromination, and a substitution by a secondary α-silylmethyl amine. After optimization of the photocyclization, the reaction delivered tetrahydroisoquinolines in moderate to high yields (41-83percent). A facial diastereoselectivity (dr ? 80:20) was observed with chiral substrates and a crystal structure provided evidence for the relative configuration of the major diastereoisomer. A catalytic cycle with direct electron transfer to the photoexcited metal catalyst is proposed.
Nitrogen Assistance in Intramolecular Nickel-Promoted Tandem Cyclization-Quenching Processes
Sole, Daniel,Cancho, Yolanda,Llebaria, Amadeu,Moreto, Josep M.,Delgado, Antonio
, p. 5895 - 5904 (2007/10/03)
A diastereoselective and mild cyclization-quenching process based on the treatment of nitrogen-tethered halodienes with stoichiometric Ni(COD)2 is described. The success of this methodology relies on the presence of a distal amino group capable of coordin
