Construction of a Polycyclic Conjugated System Containing a Dibenzazepine Moiety by Cationic Gold(I)‐Catalyzed Cycloisomerization

Abstract

A new π‐conjugated system of nitrogen‐containing polycyclic compounds was constructed by cationic AuI‐catalyzed cycloisomerization. Intramolecular reaction of 9‐(2‐alkynylphenyl)‐9H‐carbazole derivatives gave a variety of penta‐ and hexacyclic compounds possessing a dibenzazepine skeleton. The rigid carbazole structure was responsible for efficient 7‐endo‐dig cycloisomerization.

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

“… Reagents and conditions: (a) 560 AuCl(PPh 3 ) (10 mol %), AgSbF 6 (10 mol %), 1,2-DCE, 80 °C, 24 h; (b) AuCl[P(C 6 F 5 ) 3 ] (10 mol %), AgOTf (10 mol %), 1,2-DCE, rt, 3 h; (c) 518 Cs 2 CO 3 , CuI, DMF, microwave, 150 °C, 10 min; (d) 517 AcCl (1.2 equiv), Et 3 N (2.0 equiv), DCM, rt, 4 h; (e) polyphosphoric acid, POCl 3 (10 equiv) 120 °C, 3 h. …”

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

“…Among acyclic substrates able to undergo a metal-promoted cyclization to give a polycyclic heterocycle, functionalized alkynes bearing a suitably placed heteronucleophile play a major role, as the triple bond can be easily electrophilically activated by a suitable metal species thus promoting the cyclization by intramolecular nucleophilic attack [ 1 , 2 , 3 , 4 , 5 ]. Usually, processes like these are promoted by costly metals (mainly gold [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], palladium [ 20 , 21 , 22 , 23 ], rhodium [ 24 , 25 , 26 ], platinum [ 27 , 28 , 29 ], and, occasionally, ruthenium [ 30 ]), while the use of less expensive metal species, such as cobalt [ 31 ], nickel [ 32 ], copper [ 33 , 34 , 35 , 36 ], zinc [ 37 , 38 , 39 , 40 ], and silver [ 41 , 42 ] compounds, has been scantly reported in the literature, and applied to a limited number of examples.…”

Catalytic Enantioselective Synthesis of Azepine-Fused Planar-Chiral Ferrocenes by Pt-Catalyzed Cycloisomerization

“…3 Recently, our group developed a synthesis of dibenzo [b,f ]azepine derivatives by the Au-catalyzed 7-endo-dig-selective cycloisomerization of 2-alkynyl-N-arylanilines (Scheme 1b). 4 However, to the best of our knowledge, there have been no previous reports of the enantioselective synthesis of dibenzazepine derivatives. 5 Cramer and co-workers recently reported an elegant work on Pd-catalyzed intramolecular C−H arylation for the enantioselective synthesis of axially chiral dibenzazepinones (Scheme 1c).…”

“…Buchwald and co-workers reported a Pd-catalyzed consecutive Buchwald–Hartwig amination and Heck reaction to provide dibenzo­[ b , f ]­azepine derivatives (Scheme a) . Recently, our group developed a synthesis of dibenzo­[ b , f ]­azepine derivatives by the Au-catalyzed 7- endo - dig -selective cycloisomerization of 2-alkynyl- N -arylanilines (Scheme b) . However, to the best of our knowledge, there have been no previous reports of the enantioselective synthesis of dibenzazepine derivatives .…”

“…Isolated by preparative TLC (hexane/dichloromethane = 1/4, R f = 0.6). The title compound was obtained as an orange solid (14 4. mg, 0.035 mmol): mp 93 °C; 1 H NMR δ 7.54 (d, J = 1.7 Hz, 1H), 7.21 (d, J = 8.0 Hz, 1H), 7.09 (dd, J = 8.1, 1.8 Hz, 1H), 6.26 (d, J = 1.3 Hz, 1H), 4.89−4.86 (m, 1H), 4.48−4.45 (m, 1H), 4.39−4.36 (m. 1H), 4.06 (s, 5H), 2.43 (s, 3H), 2.28 (s, 3H), 2.21 (d, J = 1.3 Hz, 3H); 13 C NMR δ 138.2, 136.9, 136.7, 135.9, 131.3, 129.9, 128.7, 124.2, 83.3, 82.5, 71.4, 71.0, 68.6, 68.3, 38.2, 21.4, 19.4; HRMS (ESI, positive) m/z calcd for C 21 H 21 FeNO 2 S (M + ) 407.0637, found 407.0633; [α] 34 D = 478 (c 0.33, CHCl 3 , 71% ee).…”