Visible-Light-Promoted Selenylation/Cyclization of o-Alkynyl Benzylazides/o-Propargyl Arylazides: Synthesis of Seleno-Substituted Isoquinolines and Quinolines
Ag-catalyzed cyclization of 2-alkynylbenzylazides offers a novel and efficient method for the synthesis of substituted isoquinoline. The reaction proceeds smoothly in moderate to good yields and tolerates considerable functional groups. The reaction conditions and the scope of the process are examined, and a plausible mechanism is proposed.
A PdI2/I2-catalyzed thiolation-annulation route of alkynes with azides and disulfides for the synthesis of 4-sulfenylisoquinolines is described. This route allows numerous 2-alkynylbenzyl azides to react with disulfides or 1,2-diphenyldiselane leading to the corresponding 4-chalcogen-substituted isoquinolines in moderate to good yields.
Synthesis of Isoquinolylselenocyanates and Quinolylselenocyanates via Electrophilic Selenocyanogen Cyclization Induced by Pseudohalogen (SeCN)
<sub>2</sub>
Generated
<i>in situ</i>
A strategy for the synthesis of isoquinolylselenocyanates and quinolylselenocyanates through electrophilicselenocyanogencyclization has been developed. The feature of this reaction is that the sequential process was induced directly by generated in situpseudohalogen (SeCN)2generated in situ. Additionally, the obtained selenocyanates allowed functional group diversification, which could be potential
practical Tf2O-catalyzed tandem cyclization/trifluoromethylselenolation of alkynes with EtOH as the green solvent was developed. Various CF3Se-containing heterocycliccompounds, including indoles, benzofurans, benzothiophenes, isoquinolines and chromenes have been synthesized with trifluoromethyl selenoxides as CF3Se source.