Synthesis of 8-aryl substituted benzo[a]phenanthridine derivatives by consecutive three component tandem reaction and 6-endo carbocyclization

Gold(I)-Catalyzed Activation of Alkynes for the Construction of Molecular Complexity

“…360c This type of transformation has been applied to the synthesis of 5,8-diiodo- and 6,13-diiodobenzo[ k ]tetraphenes 415 (Scheme 133 ), 362 as well as to the synthesis of benzo[ a ]phenanthridines from 3-alkynyl-4-arylisoquinolines. 363 It has been proposed that the most favored reaction pathway features an initial 6- endo -dig hydroarylation of the alkyne followed by 1,2-H shift and formation of a gold-carbene intermediate, which then undergoes a 1,2-halogen shift to finally give the rearranged product after deauration. 364 The reaction of ( o -arylphenyl)alkynylselenides in the presence of gold(I) and gold(III) affords rearranged phenanthrenyl selenides very efficiently by migration of the selenide from the terminal to the internal position of the alkyne.…”

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

“…Because of the recent strong focus on benzophenanthridines due to their potent antitumor and antiinfectious activities [ 43 ], we have chosen one recent synthetic approach (differing from afore listed examples) to benzo[ a ]phenanthridines as close analogues of phenanthridine ( Scheme 20 ) [ 44 ]. The synthesis by multicomponent tandem reaction/carbocyclization starts with the formation of a 4-aryl-3-arylethynylisoquinoline from 2-bromobenzaldehyde/ tert -butylamine/1,3-diyne.…”

Cycloaddition of 1,3-Butadiynes: Efficient Synthesis of Carbo- and Heterocycles

“…On the basis of the cycloaddition reactions of two carbon-carbon triple bonds, 1,3-butadiynes have been one of the simple and efficient starting materials for the formation of polyaromatic compounds. For example, 8-aryl-substituted benzo[a]phenanthridine derivatives could be obtained by consecutive three component tandem reactions of 2-bromobenzaldehydes, t -butylamine and 1,3-butadiynes involving palladium-catalyzed cyclocondensation of 1,3-butadiynes with (2-bromobenzylidene)- t -butylamine generated in situ giving 3-alkynyl isoquinoline intermediates, which then underwent 6-endo carbocyclization in the presence of AuCl(PPh 3 )/AgSbF 6 (Scheme 16) [37].…”