Divergent Synthesis of Imidazoles and Quinazolines via Pd(OAc)2-Catalyzed Annulation of N-Allylamidines
摘要:
A Pd(OAc)(2)-catalyzed divergent synthesis of multisubstituted imidazoles and quinazolines from N-allylamidines has been developed. In the presence of oxidant O-2 from air and/or a ligand and Pd(OAc)(2) imidazoles were obtained. Nonetheless, under microwave (MW) irradiation in a sealed system, quinazolines as major products were produced.
Divergent Synthesis of Imidazoles and Quinazolines via Pd(OAc)2-Catalyzed Annulation of N-Allylamidines
摘要:
A Pd(OAc)(2)-catalyzed divergent synthesis of multisubstituted imidazoles and quinazolines from N-allylamidines has been developed. In the presence of oxidant O-2 from air and/or a ligand and Pd(OAc)(2) imidazoles were obtained. Nonetheless, under microwave (MW) irradiation in a sealed system, quinazolines as major products were produced.
Solvent/Oxidant-Switchable Synthesis of Multisubstituted Quinazolines and Benzimidazoles via Metal-Free Selective Oxidative Annulation of Arylamidines
作者:Jian-Ping Lin、Feng-Hua Zhang、Ya-Qiu Long
DOI:10.1021/ol500864r
日期:2014.6.6
A fast and simple divergent synthesis of multisubstituted quinazolines and benzimidazoles was developed from readily available amidines, via iodine(III)-promoted oxidative C(sp(3))-C(sp(2)) and C(sp(2))-N bond formation in nonpolar and polar solvents, respectively. Further selective synthesis of quinazolines in polar solvent was realized by TEMPO-catalyzed sp(3)C-H/sp(2)C-H direct coupling of the amidine with K2S2O8 as the oxidant. No metal, base, or other additives were needed.
Functional group manipulation via organoselenium- and halogen-induced cyclofunctionalization/hydrolysis of allylic benzimidates, tertiary benzamides, and benzamidines. Regioflexible synthesis of amino alcohol derivatives
作者:Lars Engman
DOI:10.1021/jo00061a009
日期:1993.4
Allylic benzimidates were treated with benzeneselenenyl halides in chloroform or acetonitrile to give, via 5-exo cyclofunctionalization/hydrolysis, 3-(benzoyloxy)-2-(phenylamino)-1-(phenylselenenyl)-alkanes in fair yields. Allylic tertiary benzamides afforded 2-(benzoyloxy)-3-(phenylamino)-1-(phenylselenenyl)alkanes when submitted to similar reaction conditions. Bromoalkanes, functionalized in an analogous way, were obtained after hydrolytic workup when bromine was added to allylic benzimidates and tertiary benzamides. In some of these reactions, products of 6-endo cyclofunctionalization/hydrolysis (1-(benzoyloxy)-3-(phenylamino)-2-bromoalkanes) were also formed. The addition of benzeneselenenyl bromide to some a-substituted allylic benzimidates and tertiary benzamides was diastereoselective (0 < de < 90%, depending on conditions) with a preference for threo isomer formation. Hydrodeselenation/hydrodebromination of the cyclofunctionalization/hydrolysis products was efficiently effected (88-100% yield) by treatment of the products with triphenyltin hydride in refluxing benzene containing a catalytic amount of azobis(isobutyronitrile). The proper choice of allylic benzimidate/tertiary benzamide allowed the preparation of amino alcohol derivatives in which the 1,2-orientation of the functional groups, relative to the carbon backbone, could be varied in a controlled and predictable manner. The regioflexibility of the process was demonstrated for primary, secondary, and tertiary positions. When allylic benzamidines were submitted to the cyclofunctionalization/hydrolysis reaction conditions using benzeneselenenyl bromide as the electrophilic reagent, 5-phenylselenenyl(methyl) -substituted dihydroimidazoles were obtained.
Divergent Synthesis of Imidazoles and Quinazolines via Pd(OAc)<sub>2</sub>-Catalyzed Annulation of <i>N</i>-Allylamidines
作者:Li Xu、Hongxian Li、Ziyang Liao、Kaiyan Lou、Hexin Xie、Hao Li、Wei Wang
DOI:10.1021/acs.orglett.5b01435
日期:2015.7.17
A Pd(OAc)(2)-catalyzed divergent synthesis of multisubstituted imidazoles and quinazolines from N-allylamidines has been developed. In the presence of oxidant O-2 from air and/or a ligand and Pd(OAc)(2) imidazoles were obtained. Nonetheless, under microwave (MW) irradiation in a sealed system, quinazolines as major products were produced.