Palladium-catalyzed cascade reactions of coumarins with alkynes: synthesis of highly substituted cyclopentadiene fused chromones

Lei Wang, Shiyong Peng, Jian Wang
2011 Chemical Communications  
Chemicals and solvents were purchased from commercial suppliers and used as received. 1 H and 13 C NMR spectra were recorded on a Bruker ACF300 (300 MHz) or a AMX500 (500 MHz) spectrometer. Chemical shifts were reported in parts per million (ppm), and the residual solvent peak was used as an internal reference: proton (chloroform δ 7.26), carbon (chloroform δ 77.0) or tetramethylsilane (TMS δ 0.00) was used as a reference. Multiplicity was indicated as follows: s (singlet), d (doublet), t
more » ... et), q (quartet), m (multiplet), dd (doublet of doublet), bs (broad singlet). Coupling constants were reported in Hertz (Hz). Low resolution mass spectra were obtained on a Finnigan/MAT LCQ spectrometer in ESI mode and API 3000™ in APCI (Heated Nebulizer) mode. All high resolution mass spectra were obtained on a Finnigan/MAT 95XL-T spectrometer. For thin layer chromatography (TLC), Merck pre-coated TLC plates (Merck 60 F254) were used, and compounds were visualized with a UV light at 254 nm. Further visualization was achieved by staining with iodine. Flash chromatography separations were performed on Merck 60 (0.040-0.063 mm) mesh silica gel. Starting materials Compounds 1 and 2, 2c, 2d were commercially available. Compounds 1b 1 , 1c 1 , 1e 1 , 1f 1 , 1h 1 , 1i 1 , , 1l 1 , 1m 1 , 1n 1 ; 1a 2 , 1g 2 ,1j 2 , 1k 2 ; 2a 3 , 2b 3 , 2e 3 , 2f 3 , 2g 3 , 2h 3 , 2i 3 , 2j 3 , 2k 3 ,2l 3 were prepared according to literature, respectively. Supplementary Material (ESI) for Chemical Communications This journal is (c) The Royal Society of Chemistry 2011 S3 Representative Procedure for Palladium-catalyzed Reaction Typical procedure for the Palladium-catalyzed Reaction: To a solution of diphenylacetylene 2a ( 178 mg, 1 mmol) and 4-hydroxycoumarin 1a (32.4 mg, 0.2 mmol) in 2 ml of dimethylacetamide, then Copper (II) bromide (89.2 mg, 0.4 mmol) as an oxidant and cesium carbonate (130.3 mg, 0.4 mmol) as an additive were added. The reaction mixture was stirred at 130 o C for 24h. The crude product was purified by column chromatography on silica gel, eluted by hexane/EtOAc = 25:1 then 10:1 to afford 70.0 mg (79% yield) of the desired product 3a as pale white powder. 4. Analytical Data of Palladium-catalyzed Reaction 1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3a). 79% yield; 1 H NMR (500 MHz, CDCl 3 ): δ = 8.31 -8.19 (m, 1H), 7.55 (dd, J = 11.3, 4.2, 1H), 7.43 -7.33 (m, 8H), 7.25 (ddd, J = 14.1, 7.1, 2.2, 9H), 7.01 (t, J = 7.3, 1H), 6.94 (t, J = 7.5, 2H), 6.83 -6.75 (m, 2H).; 13 C NMR (125 MHz, CDCl 3 ): δ = O O 7-methyl-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3b). 81% yield; 1 HNMR (500 MHz, CDCl 3 ) δ = 7.96 (s, 1H), 7.32 (ddd, J = 9.6, 7.7, 3.3 Hz, 7H), 7.25 -7.16 (m, 10H), 6.95 (t, J =7.4 Hz, 1H), 6.88 (t, J =7.6 Hz, 2H), 6.75-6.67 (m, 2H), 2.35 (s, 3H).; 13 C NMR (125 MHz, CDCl 3 ): δ = HRMS (ESI) calcd for C 37 H 27 O 2 [M+H] + 503.2006, found 503.2011. 7-isopropyl-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3c). 79% yield; 1 HNMR (500 MHz, CDCl 3 ) δ = 8.34 -7.99 (m, 1H), 7.50 (dd, J =8.6, 2.2 Hz, 1H), 7.47 -7.40 (m, 6H), 7.40 -7.35 (m, 1H), 7.35 (s, 9H), 7.06 (t, J =7.3 Hz, 1H), 6.99 (t, J=7.6, 2H), 6.86 (dd, J =19.2, 8.0 Hz, 2H), 3.04 (hept, J = 6.8 Hz, 1H), 1.30 (d, J = 6.9 Hz, 6H).; 13 C NMR (126 MHz, S5 7-ethyl-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3d). 84% yield; 1 H NMR (500 MHz, CDCl 3 ) δ = 8.10 (s, 1H), 7.47-7.38 (m, 6H), 7.36-7.28 (m, 11H), 7.05 (t, J = 7.4 Hz, 1H), 6.98 (t, J = 7.6 Hz, 2H), 6.81 (d, J = 7.3, 2H), 2.75 (q, J = 7.6 Hz, 2H), 1.27 (t, J = 7.6 Hz, 3H).; 13 C NMR (125 MHz, 15.98.; HRMS (ESI) calcd for C 38 H 29 O 2 [M+H] + 517.2162, found 5172173. O O 6,7-dimethyl-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3e). 50% yield; 1 H NMR (500 MHz, CDCl 3 ) δ = 8.01 (s, 1H), 7.45 -7.38 (m, 6H), 7.34 -7.27 (m, 9H), 7.22 (s, 1H), 7.09 -7.02 (m, 1H), 6.98 (dd, J = 10.4, 4.7, 2H), 6.85 -6.78 (m, 2H), 2.35 (s, 6H).; 13 C (125 MHz, S7 6-methoxy-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3h). 62% yield; 1 H NMR (500 MHz, CDCl 3 ) δ = 8.15 (d, J = 8.9 Hz, 1H), 7.39 (td, J =7.6, 2.7 Hz, 6H), 7.33 -7.24 (m, 9H), 7.02 (t, J =7.3 Hz, 1H), 6.94 (dd, J =13.5, 5.9 Hz, 3H), 6.82 -6.77 (m, 3H), 3.82 (s, 3H).; 13 C NMR (125 MHz, HRMS (EI) calcd for [M+H] + C 37 H 27 O 2 519.1955, found 519.1967. 7-fluoro-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3i). 66% yield; 1 H NMR (500 MHz, CDCl 3 ) δ = 7.88 (dd, J =8.4, 3.1 Hz, 1H), 7.40-7.36 (m, 7H), 7.31-7.25 (m, 10H), 7.03 (t, J = 7.4 Hz, 1H), 6.95 (t, J = 7.6 Hz, 2H), 6.79 -6.76 (m, 2H).; 13 C NMR (125 MHz, S8 6-chloro-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3g). 68% yield; 1 H NMR (500 MHz, CDCl 3 ): δ = 8.21 (d, J = 8.6, 1H), 7.48-7.35 (m, 8H), 7.35-7.26 (m, 9H), 7.06 (t, J = 7.3 Hz, 1H), 6.98 (t, J = 7.6 Hz, 2H), 6.81 (d, J = 7.7 Hz, 2H).; 13 C NMR (125 MHz, HRMS (ESI) calcd for C 36 H 24 O 2 Cl [M+H] + 523.1459, found 523.1474. 7-chloro-1,2,3,3-tetraphenylcyclopenta[b]chromen-9(3H)-one (3h). 74% yield; 1 H NMR (500 MHz, CDCl 3 ): δ = 8.19 (t, J = 4.7 Hz, 1H), 7.51 (dd, J = 8.9, 2.6 Hz, 1H), 7.39 -7.33 (m, 7H), 7.31 -7.24 (m, 9H), 7.05 -7.00 (m, 1H), 6.95 (dd, J = 10.5, 4.8 Hz, 2H), 6.77 (t, J = 1.5 Hz, 2H).; 13 C NMR (125 MHzHRESIMS (complex as standard) calcd for C 44 H 39 O 2 Cl 2 [M+H] + 669.2337, found 669.2322.
doi:10.1039/c1cc10939a pmid:21416093 fatcat:7z7gyetinrcsnmsui6ptuugtsm