A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Page
GO
GO
?
^
Top
Org. Synth. 2009, 86, 225
DOI: 10.15227/orgsyn.086.0225
SYNTHESIS OF POLYYNES BY IN SITU DESILYLATIVE BROMINATION AND PALLADIUM-CATALYZED COUPLING: (7-(BENZYLOXY)HEPTA-1,3,5-TRIYNYL)TRIISOPROPYLSILANE
Submitted by Soonho Hwang, Hee Ryong Kang, and Sanghee Kim1.
Checked by Olesya Haze and Rick L. Danheiser.
1. Procedure
((3-Bromoprop-2-ynyloxy)methyl)benzene (1). A 500-mL, three-necked, round-bottomed flask (Note 1) equipped with a magnetic stir bar, two glass stoppers, and an argon inlet adapter is charged with benzyl propargyl ether (11.2 g, 76.6 mmol, 1.0 equiv) (Note 2), 150 mL of acetone (Note 3), and N-bromosuccinimide (15.0 g, 84.3 mmol, 1.1 equiv) (Note 2). To the resulting yellow solution, silver(I) nitrate (1.30 g, 7.65 mmol, 0.1 equiv) (Note 2) is added, and the cloudy-grey reaction mixture is stirred at 24 °C for 30 min (Notes 4, 5). The reaction mixture is transferred to a 1-L separatory funnel containing 100 mL of saturated aq Na2S2O3 solution and diluted with 200 mL of Et2O and 200 mL of pentane (Note 6). The organic layer is separated and washed with two 200 mL portions of brine, dried over MgSO4 (5 g), filtered, and concentrated by rotary evaporation (20 °C, 20 mmHg) to give 18 g of an orange oil. This material is purified by silica gel column chromatography (Note 7) to afford 14.8-15.4 g (86-89%) of bromoacetylene 1 as a light yellow oil (Note 8).
(5-(Benzyloxy)penta-1,3-diynyl)triisopropylsilane (2). A 500-mL, three-necked, round-bottomed flask equipped with a magnetic stir bar, glass stopper, rubber septum, and an argon inlet adapter is charged with bromoacetylene 1 (7.60 g, 33.8 mmol, 1.0 equiv), 230 mL of tetrahydrofuran (Note 3), and (triisopropylsilyl)acetylene (9.10 mL, 7.40 g, 40.5 mmol, 1.2 equiv) (Note 2). Dichlorobis(triphenylphosphine)palladium(II) (0.478 g, 0.68 mmol, 0.02 equiv) (Note 2) and copper(I) iodide (0.130 g, 0.68 mmol, 0.02 equiv) (Note 2) are added in one portion, and diisopropylamine (10.0 mL, 7.16 g, 70.8 mmol, 2.1 equiv) (Note 2) is added by syringe over 2 min. The resulting yellow slurry is stirred at 24 °C for 5 h, during which time the color of the slurry darkened progressively to brown (Note 9, 10). Saturated aq NH4Cl solution (25 mL) is then added, and the resulting mixture is diluted with 250 mL of Et2O and transferred to a 1-L separatory funnel. The organic layer is separated and washed with two 250 mL portions of brine, dried over anhydrous Na2SO4 (15 g, 10 min), filtered, and concentrated by rotary evaporation (25 ºC, 20 mmHg) to give 13 g of viscous brown oil. Column chromatography on silica gel (Note 11) yields 8.13-8.41 g (74-76%) of TIPS-diyne 2 as a yellow oil (Note 12).
((5-Bromopenta-2,4-diynyloxy)methyl)benzene (3). A 500-mL, three-necked, round-bottomed flask equipped with a rubber septum, glass stopper and an argon inlet adapter is charged with TIPS-diyne 2 (8.79 g, 26.9 mmol, 1.0 equiv), 135 mL of freshly distilled acetonitrile (Note 3), N-bromosuccinimide (5.75 g, 32.3 mmol, 1.2 equiv) and silver(I) fluoride (4.10 g, 32.3 mmol, 1.2 equiv) (Note 2). The reaction flask is fitted with a mechanical stirrer (Note 13) and wrapped in aluminum foil. The heterogeneous reaction mixture is stirred at 22-25 °C for 2 h (Note 14). The reaction mixture is filtered through a pad of 20 g of Celite with the aid of 100 mL of Et2O (Note 6). The filtrate is diluted with 100 mL of Et2O, transferred to a 1-L separatory funnel, washed with two 200 mL portions of brine, dried over Na2SO4 (15 g, 10 min), filtered, and concentrated by rotary evaporation (25 °C, 20 mmHg) to give 8.3 g of an orange oil. Column chromatography on silica gel (Note 15) gives 6.124 g (91%) of bromo diyne 3 (Note 16) as an orange oil (Note 17).
(7-(Benzyloxy)hepta-1,3,5-triynyl)triisopropylsilane (4). A 500-mL, two-necked, round-bottomed flask equipped with a stir bar, rubber septum, and argon inlet adapter is charged with alkynyl bromide 3 (5.90 g, 23.7 mmol, 1.0 equiv), 240 mL of tetrahydrofuran, and (triisopropylsilyl)acetylene (6.40 mL, 5.20 g, 28.5 mmol, 1.2 equiv). Dichlorobis(triphenylphosphine)palladium(II) (0.500 g, 0.71 mmol, 0.03 equiv) and copper(I) iodide (0.136 g, 0.71 mmol, 0.03 equiv) (Note 18) are added in one portion, and diisopropylamine (7.00 mL, 5.01 g, 49.5 mmol, 2.0 equiv) is added by syringe over 1 min. The resulting yellow slurry is stirred at 24 °C for 5 h, during which time the slurry darkens progressively to a deep brown color (Note 19). Saturated aq NH4Cl solution (20 mL) is then added, and the resulting mixture is transferred to a 1-L separatory funnel and diluted with 250 mL of Et2O. The organic layer is washed with two 250 mL portions of brine, dried over Na2SO4 (20 g, 10 min), filtered, and concentrated by rotary evaporation (rt, 20 mmHg) to give 5 g of a viscous black oil. Column chromatography on silica gel (Note 20) affords 3.19 g (38%) (Note 21) of triyne 4 as a brown oil (Note 22).
2. Notes
1. The checkers used flame-dried glassware and carried out the reaction under an atmosphere of argon. The submitters dried their apparatus in an oven at 80 °C for 8 h and performed the reaction under an atmosphere of nitrogen.
2. Benzyl propagyl ether (98.0%) was purchased from Acros Organics. N-Bromosuccinimide (99%) and silver(I) nitrate (99+%, ACS reagent) were purchased from Aldrich Chemical Co., Ltd. (Triisopropylsilyl)acetylene (98.0+%) was purchased from Fluka. Copper(I) iodide (99.999%), diisopropylamine (99.5%), and silver(I) fluoride (99%) were purchased from Aldrich Chemical Co., Ltd. The checkers purchased dichlorobis(triphenylphosphine)palladium(II) (99.99%) from Aldrich Chemical Co., Ltd. while the submitters obtained this catalyst (>98.0%) from Tokyo Chemical Industry Co., Ltd.
3. The checkers used acetone (HPLC grade, J. T. Baker) that was distilled under argon after drying over anhydrous K2CO3. The checkers purchased tetrahydrofuran (HPLC grade) from J.T. Baker and purified it by pressure filtration under argon through activated alumina. The checkers purchased acetonitrile (ChromAr grade) from Mallinckrodt and distilled it from CaH2. The submitters employed acetone, tetrahydrofuran, and acetonitrile that was purchased from Burdick & Jackson and dried by distillation from anhydrous K2CO3, sodium/benzophenone ketyl, and CaH2, respectively. The submitters used tetrahydrofuran after bubbling nitrogen through it for 15 min.
4. Because of the photosensitivity of NBS, AgF, and the brominated product, the reaction was protected from light by wrapping the flask with aluminum foil.
5. The progress of the reaction was monitored by TLC analysis on EMD (Merck) pre-coated glass-backed silica gel 60 F-254 250 μm plates. The plates were eluted twice with 20:1 hexanes:EtOAc, and visualized by UV absorbance at 254 nm or with KMnO4, PMA, or p-anisaldehyde stain. Benzyl propagyl ether has Rf = 0.4, and bromoacetylene 1 has Rf = 0.5.
6. Diethyl ether was obtained by the checkers from Mallinckrodt (anhydrous, stabilized, AR(r), ACS grade) and by the submitters from SK chemicals. The checkers purchased Na2S2O3·5H2O (ACS grade, ≥99.5%) from Mallinckrodt.
7. Flash column chromatography was carried out using Sorbent Technologies Standard Grade 60Å 230-400 mesh silica gel. A glass column (6 × 40 cm) was slurry-packed with 300 g of silica gel. The compound was loaded in a solution of 20:1 hexanes/EtOAc. The column was eluted with 20:1 hexanes:EtOAc, collecting an initial 300 mL fraction, and then 30 mL fractions. The fractions containing the desired product were combined and concentrated by rotary evaporation at room temperature (20 mmHg).
8. The submitters report obtaining 16.19 g (94%) of bromoacetylene 1 as a colorless oil. Characterization data for ((3-bromoprop-2-ynyloxy)methyl)benzene (1): IR (film): 3065, 3031, 2853, 2214, 1497, 1454, 1353, 1091, 1029, 738, 698 cm-1; 1H NMR pdf (400 MHz, CDCl3) δ: 4.22 (s, 2H), 4.61 (s, 2H), 7.28-7.38 (m, 5H); 13C NMR pdf (100 MHz, CDCl3) δ: 46.8, 58.2, 71.9, 76.4, 128.2, 128.3, 128.7, 137.3; Anal. calcd for C10H9BrO: C, 53.36; H, 4.03. Found: C, 53.27; H, 3.91.
9. When the reaction temperature was maintained at 30 °C, the reaction was completed within 1 h. However, the formation of homocoupling product 6 increased significantly from 1 to 8%.
10. The progress of the reaction was monitored by TLC analysis (two elutions with 50:1 hexanes/EtOAc). Under these conditions (triisopropylsilyl)acetylene Rf = 0.88, TIPS-diyne 2 Rf = 0.44, bromoacetylene 1 Rf = 0.35, and the homocoupling product 6 Rf = 0.26.
11. A glass column (6 × 40 cm) was slurry-packed with 300 g of silica gel. The product was loaded as a solution in 50:1 hexanes/EtOAc. The column was eluted with 50:1 hexanes:EtOAc, collecting an initial 500 mL fraction, and then 30-mL fractions. The fractions containing the desired product were combined and concentrated by rotary evaporation at room temperature (20 mmHg).
12. The submitters reported carrying out the reaction at 20 °C for 2 h, and obtained 8.50 - 9.10 g (77-83%) of TIPS-diyne 2 as a yellow oil. Characterization data for (5-(benzyloxy)penta-1,3-diynyl)triisopropylsilane (2): IR (film): 3066, 3032, 2944, 2891, 2866, 2105, 1497, 1462, 1384, 1352, 1241, 1073, 997, 883, 796, 736, 697, 665 cm-1; 1H NMR pdf (400 MHz, CDCl3) δ: 1.10 (s, 21H), 4.26 (s, 2H), 4.63 (s, 2H), 7.28-7.38 (m, 5H); 13C NMR pdf (100 MHz, CDCl3) δ: 11.4, 18.7, 57.8, 71.9, 72.0, 73.1, 84.6, 89.2, 128.2, 128.3, 128.6, 137.3; UV (CH3OH) λmax, nm (e): 243 (760), 255 (810), 269 (480); MS (EI) m/z (rel int) 326 (M+, 1); HRMS (EI) calcd for C21H30OSi(M+) 326.2066, found 326.2066; Anal. calcd for C21H30OSi: C, 77.24; H, 9.26. Found: C, 77.09; H, 9.37. The purity of TIPS-diyne 2 was determined by the submitters to be 97% according to HPLC analysis. HPLC analysis was performed on a Agilent 1200 series with YMC-Pack SIL column (250 × 4.6 mm), elution with EtOAc/hexane (gradient, 20% EtOAc/hexane, 25 min) at 1 mL/min while monitoring at 300 nm. The retention time of the TIPS-diyne 2 was 13.9 min.
13. The checkers found that vigorous stirring is critical to obtain consistently high yields. With magnetic stirring the checkers observed that longer reaction times (6-7 h) were required and the reaction proceeded in lower yield (30-40%). Silver(I) fluoride does not completely dissolve in the reaction mixture and without efficient stirring forms a sticky mass at the bottom of the reaction flask.
14. The progress of the reaction was monitored by TLC analysis (one elution with 20:1 hexanes/EtOAc; TIPS-diyne 2 Rf = 0.44, bromo diyne 3 Rf = 0.36).
15. A glass column (6 × 40 cm) was slurry-packed with 260 g of silica gel. The product was loaded as a solution in 20:1 hexanes/EtOAc. The column was eluted with 20:1 hexanes:EtOAc, collecting an initial 400 mL fraction, and then 225 mL fractions. The fractions containing the desired product were combined and concentrated by rotary evaporation (during concentration the colorless product slowly became yellow-orange).
16. When the reaction was carried out at half this scale (13.5 mmol) with magnetic stirring, the checkers obtained the bromo diyne in somewhat lower yield (2.83 g, 84%). The submitters report obtaining 5.91-6.24 g (88-93%) of bromo diyne 3 as a yellow oil. Bromo diyne 3 is stable to storage in a freezer (-20 °C) for at least a week. However, prolonged exposure to air and light at room temperature caused slow decomposition.
17. Characterization data for ((5-bromopenta-2,4-diynyloxy)methyl)benzene (3): IR (film): 3031, 2862, 2236, 2142, 1497, 1454, 1351, 1258, 1192, 1073, 1028, 905, 738, 697, 665 cm-1; 1H NMR pdf (400 MHz, CDCl3) δ: 4.24 (s, 2H), 4.62 (s, 2H), 7.28-7.39 (m, 5H); 13C NMR pdf (100 MHz, CDCl3) δ: 41.6, 57.6, 65.1, 71.61, 71.63, 72.0, 128.3, 128.4, 128.7, 137.1; UV (CH3OH) λmax, nm (ε): 212 (1300), 265 (3000), 304 (800); HRMS (EI) calcd for C12H9BrO (M+) 247.9837, found 247.9839. The purity of bromo diyne 3 was determined by the submitters to be 98% by HPLC analysis. HPLC analysis was performed on a Agilent 1200 series with YMC-Pack SIL column (250 × 4.6 mm), elution with EtOAc/hexane (gradient, 15% EtOAc/hexane, 25 min) at 1 mL/min while monitoring at 300 nm. The retention time of the bromo diyne 3 was 9.0 min.
18. The checkers found that when grey CuI (99.999%, from Aldrich Chemical Co., Ltd) was used as received, the product was obtained in lower yield (30-33%) and the reaction was not complete after 6 h. Improved results were obtained (38-45% yield, reaction complete within 5 h) by using white CuI obtained by purification by Soxhlet extraction with THF followed by drying at 0.05 mmHg for 24 h.
19. The progress of the reaction was monitored by TLC analysis (one elution with 20:1 hexanes/EtOAc; (triisopropylsilyl)acetylene Rf = 0.86, triyne 4 Rf = 0.41, bromo diyne 3 Rf = 0.36, and homocoupling product 7 Rf = 0.17).
20. A glass column (6 × 40 cm) was slurry-packed with 270 g of silica gel. The product was loaded as a solution in 5 mL of 50:1 hexanes/EtOAc. The column was eluted with 50:1 hexanes/EtOAc, collecting an initial 600 mL fraction, and then 30 mL fractions. The fractions containing the desired product were combined and concentrated by rotary evaporation at room temperature (20 mmHg).
21. When the reaction was carried out at half this scale (11.8 mmol), the checkers obtained diyne 3 in improved yield (1.88 g 45%). The submitters obtained 3.65-4.15 g (44-50%) of triyne 4 as a deep brown oil and report that the yield of the reaction decreases considerably as the scale increases (0.3 g scale : 75%; 1.5 g scale = 67%; 5.0 g scale = 50%).
22. Characterization data for (7-(benzyloxy)hepta-1,3,5-triynyl) triisopropylsilane: IR (film): 3032, 2944, 2891, 2866, 2164, 2078, 1497, 1462, 1384, 1350, 1282, 1075, 1018, 997, 883, 736, 697, 678, 665 cm-1; 1H NMR pdf (400 MHz, CDCl3) δ: 1.108-1.113 (m, 21H), 4.26 (s, 2H), 4.62 (s, 2H), 7.28-7.38 (m, 5H); 13C NMR pdf (100 MHz, CDCl3) δ: 11.4, 18.7, 57.7, 60.3, 63.9, 71.7, 72.0, 74.5, 85.5, 89.7, 128.25, 128.34, 128.7, 137.0; UV (CH3OH) λmax, nm (ε): 222 (75000), 285 (1000), 303 (1200), 354 (600); MS (EI) m/z (rel int) 350 (M+, 2); HRMS (EI) calcd for C23H30OSi (M+) 350.2066, found 350.2063; Anal. calcd for C23H30OSi: C, 78.80; H, 8.63. Found: C, 78.67; H, 8.43. The purity of triyne 4 was determined to be 96% by HPLC analysis under the conditions described in Note 17 (retention time of 4 was 13.9 min).
Handling and Disposal of Hazardous Chemicals
The procedures in this article are intended for use only by persons with prior training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011 www.nap.edu). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices.
These procedures must be conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.
3. Discussion
Unsymmetrically substituted conjugated diyne and polyyne units continue to attract widespread interest because of their unusual electrical, optical, and structural properties.2 Consequently, the development of efficient synthetic approaches toward these rigid units remains an important challenge to synthetic organic chemists.2-4
The method most commonly used for the preparation of unsymmetrical diyne and polyyne compounds is the Cadiot-Chodkiewicz coupling reaction,5 the metal-catalyzed cross-coupling of a 1-haloalkyne with a terminal alkyne. The major limitation of this coupling reaction, however, is that terminal diynes and higher polyynes required as coupling partners or precursors of 1-haloalkynes are often unstable.2,3,6 To overcome this challenge, many elegant alternative methods have been explored.
We have developed an iterative strategy for the synthesis of unsymmetrically substituted polyynes as shown in Scheme 1. The key to the success of this iterative method lies in the in situ one-pot desilylative bromination, which avoids the complication encountered with the isolation of sensitive terminal alkynes.
In this process, the starting terminal alkyne was first converted to bromoalkyne under standard NBS/AgNO3 conditions.7 At this point, we employed TIPS-acetylene as a cross-coupling partner for the homologation reactions because it had previously been reported that TMS-acetylene decomposes under the basic conditions of the coupling reaction such that no desired cross-coupling product can usually be isolated.8 When we used TIPS-acetylene, the desired cross-coupling product was obtained in good yield under the modified Sonogashira conditions. Our initial attempts to effect the in situ one-pot desilylative bromination of TIPS-diyne used the standard NBS/AgNO3 conditions developed by Isobe and co-workers for the conversion of TMS-protected acetylenes to bromoacetylenes.9 Unfortunately, these conditions led only to the recovery of the starting material. On the other hand, when we employed AgF instead of AgNO3, we could obtain the desired bromo diyne in high yield. Repeating the two-step acetylene homologation sequence on this bromo diyne then generated the expected bromo triyne readily in good overall yield.
Scheme 1. General Iterative Protocol for Synthesis of Unsymmetrical Polyynes.
Scheme 1. General Iterative Protocol for Synthesis of Unsymmetrical Polyynes.
Scheme 2. Total synthesis of (S)-(E)-15,16-dihydrominquartynoic acid.
Scheme 2. Total synthesis of (S)-(E)-15,16-dihydrominquartynoic acid.
By employing our new iterative strategy, we accomplished the total synthesis of (S)-(E)-15,16-dihydrominquartynoic acid from a simple stating material in a high overall yield (Scheme 2).10 In addition, we have developed a facile solid-phase synthetic pathway to generate a library of natural product-like polyynes.11 These results demonstrate that our approach can be applied efficiently to the synthesis of various unsymmetrical polyynes.
References and Notes
  1. College of Pharmacy, Seoul National University, San 56-1, Shilim, Kwanak, Seoul 151-742, Korea.
  2. (a) Ginsburg, E. J.; Gorman, C. B.; Grubbs, R. H. In Modern Acetylene Chemistry; Stang, P. J., Diederich, F., Eds.; VCH: Weinheim, 1995. (b) Brandsma, L. Preparative Acetylenic Chemistry; Elsevier: Amsterdam, 1988.
  3. For recent papers that include a discussion of this topic, see: (a) Heuft, M. A.; Collins, S. K.; Yap, G. P. A.; Fallis, A. G. Org. Lett. 2001, 3, 2883-2886. (b) Shi Shun, A. L. K.; Chernick, E. T.; Eisler, S.; Tykwinski, R. R. J. Org. Chem. 2003, 68, 1339-1347.
  4. For reviews, see: (a) Hartung, R. E.; Paquette, L. A. Chemtracts 2002, 15, 106-116. (b) Siemsen, P.; Livingston, R. C.; Diederich, F. Angew. Chem., Int. Ed. 2000, 39, 2632-2657.
  5. Cadiot, P.; Chodkiewicz, W. In Chemistry of Acetylenes; Viehe, H. G., Ed., Marcel Dekker: New York, 1969; pp. 597-647.
  6. (a) Haley, M. M.; Bell, M. L.; English, J. J.; Johnson, C. A.; Weakley, T. J. R. J. Am. Chem. Soc. 1997, 119, 2956-2957. (b) Patel, G. N.; Chance, R. R.; Turi, E. A.; Khanna, Y. P. J. Am. Chem. Soc. 1978, 100, 6644-6649. (c) Haley, M. M.; Bell, M. L.; Brand, S. C.; Kimball, D. B.; Pak, J. J.; Wan, W. B. Tetrahedron Lett. 1997, 38, 7483-7486.
  7. Hofmeister, H.; Annen, K.; Laurent, H.; Wiechert, R. Angew. Chem. Int. Ed. Engl. 1984, 23, 727-729.
  8. (a) Marino, J. P.; Nguyen, H. N. J. Org. Chem. 2002, 67, 6841-6844. (b) Eastmond, R.; Walton, D. R. M. Tetrahedron 1972, 28, 4591-4599. (c) Eaborn, C.; Walton, D. R. M. J. Organomet. Chem. 1965, 4, 217-228.
  9. Nishikawa, T.; Shibuya, S.; Hosokawa, S.; Isobe, M. Synlett 1994, 485-486.
  10. Kim, S.; Kim, S.; Lee, T.; Ko, H.; Kim, D. Org. Lett. 2004, 6, 3601-3604.
  11. Lee, S.; Lee, T.; Lee, Y. M.; Kim, D.; Kim, S. Angew. Chem. Int. Ed. 2007, 46, 8422-8425.

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

Benzyl propagyl ether; (4039-82-1)

N-bromosuccimide: NBS; (128-08-5)

Silver nitrate; (7761-88-8)

(Triisopropylsilyl)acetylene: Ethynyltriisopropylsilane; (89343-06-6)

Dichlorobis(triphenylphosphine)palladium(II): Bis(triphenylphosphine)palladium(II) Dichloride; (13965-03-2)

Copper(I) iodide: Cuprous iodide; (7681-65-4)

Diisopropylamine: DIPA; (108-18-9)

Silver(I) fluoride; (7775-41-9)

Sanghee Kim received his B.S. degree in pharmacy from Seoul National University in 1988, where he also obtained his M.S. degree in medicinal chemistry in 1990. After finishing military service as a lieutenant, he worked for a year as an assistant researcher at the Korea Institute of Science and Technology. In 1992, he joined Prof. Jeffery Winkler's group at the University of Pennsylvania and earned his Ph.D. in organic chemistry in 1997. After two years as a postdoctoral fellow with Prof. K.C. Nicolaou, at The Scripps Research Institute, he worked at Abbott Laboratories as a research scientist. He moved to Seoul National University in 1999, where he is currently a professor of college of pharmacy teaching various advanced courses in the field of medicinal and synthetic chemistry.
Soonho Hwang was born in 1983 in Daejeon, Korea and received his B.S. degree in pharmacy from Wonkwang University in 2007. In 2007, he began his graduate studies at the Seoul National University, under the guidance of Prof. Sanghee Kim. His research focuses on the total synthesis of natural products, mainly base on the palladium-catalyzed cross-coupling and [3,3]-sigmatropic Claisen rearrangement.
Hee Ryong was born in 1979 in Yesan, Korea. After finishing military service, he received his B.S. degree in chemistry from Kongju University in 2005. He completed his M.S. degree in 2007 at Seoul National University, where he worked on "Signal Regulator Synthesis Laboratory" under the supervision of Prof. Sanghee Kim. His thesis included discussions of the utilities of trialkylsilyl acetylene and AgF system. Currently, he works at the pharmaceutical company Chong Kun Dang as a medicinal chemist.
Olesya Haze graduated from the University of Rochester in 2006 with a B.S. degree in Chemistry and a B.A. degree in Mathematics. As an undergraduate she studied silane cation radical fragmentations and bonded exciplexes under the guidance of Professor Joseph Dinnocenzo. Currently Olesya is a graduate student at the Massachusetts Institute of Technology where she is developing photochemical benzannulation reactions for the synthesis of highly substituted heteroaromatic compounds in the laboratory of Professor Rick Danheiser.
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved
  Home | About OrgSyn | Contact Us | Follow Us via  
Published by Organic Syntheses, Inc.
ISSN 2333-3553 (online)
ISSN 0078-6209 (print) 
We use cookies to help understand how people use our website.
By using our site, you agree to our use of cookies
This site is powered by
VPInformatics
Life Science Data Management
Copyright© 2024 | All Rights Reserved