CuBr₂-promoted cyclization and bromination of arene–alkynes: C–Br bond formation via reductive elimination of Cu(iii) species

Abstract

A CuBr 2 -promoted cyclization and bromination of arene-alkyne substrates has been developed, affording 9-bromophenanthrene derivatives highly efficiently. This reaction provides a novel and efficient protocol for C-Br bond formation from an inorganic bromine source via the reductive elimination of the Cu(III) species.Scheme 1 Some carbon-halogen bond formation reactions. † Electronic supplementary information (ESI) available. CCDC 1438272. For ESI and crystallographic data in CIF or other electronic format see

AlCl3-Catalyzed Intramolecular Hydroarylation of Arenes with Alkynes

“…1 (2) 9-(p-Tolyl)phenanthrene (2c) 3 The reaction of 1c (107 mg, 0.4 mmol), AlCl3 (3 mg, 0.02 mmol), and anhydrous CH2Cl2 (6 mL) afforded 2c as a solid (75 mg, 70%). 1…”

“…(4) 9-Phenylphenanthrene (2e) 3 The reaction of 1e (102 mg, 0.4 mmol), AlCl3 (3 mg, 0.02 mmol), and anhydrous CH2Cl2 (6 mL) afforded 2e as a liquid (53 mg, 52%). 1 (5) 9-(4-Chlorophenyl)phenanthrene (2f) 3…”

“…The reaction of 1m (131 mg, 0.4 mmol), AlCl3 (3 mg, 0.02 mmol), and anhydrous CH2Cl2 (6 mL) afforded 2m as a solid (121 mg, 92%). 1 (12) 10-(4-Methoxyphenyl)-6-methyl-2-hydroxylphenanthrene (2n) 3 The reaction of 1n (126 mg, 0.4 mmol), AlCl3 (3 mg, 0.02 mmol), and anhydrous CH2Cl2 (6 mL) afforded 2n as a solid (120 mg, 95%). 1 H NMR (400 MHz, CDCl3) δ 8.63 (d, J = 8.8 Hz, 1 H), 8.37 (s, 1 H), 7.73 (d, J = 8.0 Hz, 1 H), 7.58 (s, 1 H), 7.43 (d, J = 8.4 Hz, 2 H), 7.36 (d, J = 6.8 Hz, 1 H), 7.24 (d, J = 6.4 Hz, 1 H), 7.20 (dd, J = 8.8, 2.8 Hz, 1 H), 7.02 (d, J = 8.4 Hz, 2 H), 5.08 (s, 1 H), 3.89 (s, 3 H), 2.61 (s, 3 H).…”

“…9-(p-Tolyl)phenanthrene (2c)3 The reaction of 1c (107 mg, 0.4 mmol), AlCl3 (3 mg, 0.02 mmol), and anhydrous CH2Cl2 (6 mL) afforded 2c as a solid (75 mg, 70%) 1. H NMR (400 MHz, CDCl3) δ 8.76 (d, J = 8.0 Hz, 1 H), 8.71 (d, J = 8.0 Hz, 1 H), 7.94 (d, J = 8.4 Hz, 1 H), 7.88 (d, J = 7.6 Hz, 1 H), 7.68-7.57 (m, 4 H), 7.52 (t, J = 7.4 Hz, 1 H), 7.44 (d, J = 8.0 Hz, 2 H), 7.32 (d, J = 7.6 Hz, 2 H), 2.47 (s, 3 H).…”

“…The solvent was removed and the residue was purified by flash chromatography on silica gel (eluent: petroleum ether) to afford 2a as a solid (108 mg, 94%). 1 The following compounds were prepared according to General Procedure I.…”