Total synthesis of glycomaurrol and eustifoline-C by DIBAL-H promoted reductive ring opening of pyrano[2,3-c]carbazoles

First Total Synthesis of the Cytotoxic Carbazole Alkaloid Excavatine‐A and Regioselective Annulation to Pyrano[2,3‐a]carbazoles and [1,4]Oxazepino[2,3,4‐jk]carbazoles

“…Our initial approach to excavatine‐A ( 1 ) was based on the introduction of the prenyl substituent by the diisobutylaluminum hydride (DIBAL‐H) promoted pyran ring opening of pyrano[2,3‐ a ]carbazoles 6 developed in our laboratories (Scheme ) . The nitrile or methoxycarbonyl group of 6 would also be reduced under these conditions and thus simultaneously furnish the formyl substituent at C‐3 of excavatine‐A ( 1 ).…”

Synthesis of 1,1′‐ and 2,2′‐Bicarbazole Alkaloids by Iron(III)‐Catalyzed Oxidative Coupling of 2‐ and 1‐Hydroxycarbazoles

“…Herein, we report the synthesis of the 1,1′‐coupled bis‐2‐hydroxy‐3‐methylcarbazole ( 1 ), the methoxy‐substituted 1,1′‐bicarbazole‐2,2′‐diols 2 – 5 , bisglybomine B ( 6 ), the bi(pyrano[3,2‐ a ]carbazoles) 7 – 9 , and the 2,2′‐bicarbazoles 10 – 12 by oxidative coupling of the corresponding monomeric carbazole alkaloids (Figure and Figure ). The carbazoles are available by our molybdenum‐mediated, iron‐mediated and palladium‐catalyzed approaches. The present report complements our recent syntheses of methylene‐bridged biscarbazoles based on an Ullmann‐type coupling of carbazole units as key step …”

Synthesis of Tetranuclear Palladium(II) Complexes and Their Catalytic Activity for Cross‐Coupling Reactions

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Herein, we report the synthesis of the 1,1'-coupled bis-2-hydroxy-3-methylcarbazole (1), the methoxy-substituted 1,1'-bicarbazole-2,2'-diols 2-5,b isglybomineB ( 6), the bi(pyrano[3,2-a]carbazoles) 7-9,a nd the 2,2'-bicarbazoles 10-12 by oxidative coupling of the corresponding monomeric carbazole alkaloids (Figure 1a nd Figure 2). The carbazoles are availableb yo ur molybdenum-mediated, [25,26] iron-mediated [27][28][29] andp alladium-catalyzed [30][31][32][33][34][35][36][37][38][39][40][41] approaches. The present report complementso ur recent syntheses of methylenebridged biscarbazolesb ased on an Ullmann-typec oupling of carbazole units as key step.…”