An anti-carbonickelative cyclization via reversible alkenylnickel E/Z isomerization of 2-azido phenyl propargyl alcohols with aryl boronic acids is achieved using Ni(acac)2 as the catalyst to access 2,3-diaryl quinolines. It represents a rare example of trapping the vinyl metal intermediate with a nitrogen center, a non-carbon center electrophile.
A novel and efficient strategy for one-step synthesis of allylated quinolines and isoquinolines via palladium-catalyzed cyclization-allylation of azides and allyl methyl carbonate is developed for the first time. The results indicated that the regioselective synthesis of allyl- and diallyl-substituted quinolines/isoquinolines depends on different substituted groups at R(1) and R(4) positions, such
Allenyl Azide Cycloaddition Chemistry. 2,3-Cyclopentennelated Indole Synthesis through Indolidene Intermediates
作者:Ken S. Feldman、D. Keith Hester、Malliga R. Iyer、Paul J. Munson、Carlos Silva López、Olalla Nieto Faza
DOI:10.1021/jo900659w
日期:2009.7.17
The thermal, photochemical, and photochemical/CuI-mediated cascade cyclizations of a range of substituted 1-(2-azidophenyl)-3-alkenylallenes are described. These reactions provide both 1,2- and 2,3-cyclopentennelated indole products in varying ratios. In most cases, high regioselectivity for the 2,3-annelated isomer can be achieved under the hv/CuI conditions. Computational studies of this multistep reaction support the intermediacy of indolidene intermediates whose electrocyclizations (with or without copper present) define the regioselectivity branch point in the sequence.
Allenyl Azide Cycloaddition Chemistry. Photochemical Initiation and CuI Mediation Leads to Improved Regioselectivity
作者:Ken S. Feldman、D. Keith Hester、Carlos Silva López、Olalla Nieto Faza
DOI:10.1021/ol800429j
日期:2008.4.1
Irradiation of 2-(3-alkenyl)allenylphenyl azides in the presence of excess Cul furnished functionalized 2,3-cyclopentenylindoles in good yield with only trace amounts of competitive C-N-bonded regioisomeric products. These results represent a significant departure from the modestto-nonexistent regioselectivity that attended thermal cyclization of these allenyl azide substrates.
Efficient approach to allylated quinolines via palladium-catalyzed cyclization–allylation of 1-azido-2-(2-propynyl) benzenes with allyl methyl carbonate
The palladium-catalyzed cyclization-allylation reaction of ortho-azido propynylbenzenes 1 and ally' methyl carbonate 2d gives the corresponding allylated quinolines in moderate to good yields. The reaction of 1-azido-2-(2-propynyl)benzene la proceeds smoothly with 10 mol % Pd(PPh3)(4) and 5 equiv K3PO4 or NaOAc in DMF at 100 degrees C to afford 3,4-diallylquinoline 3a in 69% yield in the case of R-2 = H and 3-allylquinoline 4 in 67% yield in the case of R-2 not equal H. (C) 2014 Elsevier Ltd. All rights reserved.