A Quick Procedure for the Partial Reduction of Triple Bonds

Aerssens, M. H. P. J.; Heiden, R. van der; Heus, M. de; Brandsma, L.

doi:10.1080/00397919008051583

Cited by 47 publications

(39 citation statements)

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“…Subsequently, a solution of 20 (Wako Chemical, 21.5 g, 154 mmol) in dry THF (20 mL (30), 70 (19), 67 (33), 55 (27), 41 (29). HRMS calcd for C 8 H 12 [(M-H 2 O) + ]: 108.0939, found: 108.0936.…”

Section: 5-octadiyn-1-ol (22)mentioning

confidence: 99%

“…Preparation of (R)-27 was executed by asymmetric acetylation of (±)-1-trimethylsilyl-1-undecyn-3-ol with vinyl acetate and lipase PS to give its (R)-acetate and the recovered (S)-alcohol. 3 In 2013, lipase PS coated with an ionic liquid [IL1 : α-cetylpolyoxyethylene (19)ether sulfate] was reported by Itoh and his co-workers to be more active than Amano's commercial lipase PS. 30 +25.2 (c 1.06, hexane).…”

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confidence: 98%

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Pheromone synthesis. Part 257: Synthesis of methyl (2E,4Z,7Z)-2,4,7-decatrienoate and methyl (E)-2,4,5-tetradecatrienoate, the pheromone components of the male dried bean beetle, Acanthoscelides obtectus (Say)

Mori¹

2015

Tetrahedron

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Section: 5-octadiyn-1-ol (22)mentioning

confidence: 99%

mentioning

confidence: 98%

Pheromone synthesis. Part 257: Synthesis of methyl (2E,4Z,7Z)-2,4,7-decatrienoate and methyl (E)-2,4,5-tetradecatrienoate, the pheromone components of the male dried bean beetle, Acanthoscelides obtectus (Say)

Mori¹

2015

Tetrahedron

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“…After the Sonogashira coupling between 7 and 2-iodoformanilide (9), partial reduction of the triple bond was examined. Whereas the use of the Lindlar catalyst, Pd/C, nickel boride, [9] or diimide [10] resulted in no reaction or overreduction, treatment with Zn/LiCuBr 2 in ethanol [11] gave the desired product 11 along with the corresponding amine. The use of 2,2,2-trifluoroethanol [12] as the solvent suppressed the undesired solvolysis and improved the yield of 11 to 99 %.…”

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confidence: 95%

Total Synthesis of Tryprostatins A and B

et al. 2010

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Multiple-drug resistance toward cell-cycle inhibitors frequently becomes an obstacle in cancer chemotherapy. One strategy for circumventing this problem is to develop antimitotic agents that operate by a new mode of action. Two such compounds, tryprostatins A and B, were isolated in 1995 from the fermentation broth of Aspergillus fumigatus BM939 by Osada and co-workers.[1] Tryprostatin A holds great promise, because it selectively arrests the cell cycle at the mitotic phase in tsFT210 cells.[2] Interesting biological activity combined with an apparently simple structure has stimulated the synthetic community, and several total syntheses have already been reported. [3,4] Our research group has long been involved with the radical-mediated construction of a variety of indole cores and the application of these methods to natural product synthesis. [5,6] We envisioned that our method could also be applied to the synthesis of the 2,3-disubstituted indole moiety of the tryprostatins. The interesting structural features as well as the therapeutic potential of tryprostatin A analogues indicated in a recent structure-activity-relationship study [4e] prompted us to launch a program toward the synthesis of tryprostatins.We reasoned that radical-mediated cyclization and subsequent palladium-mediated coupling with a prenyl-group donor would enable facile construction of the 2,3-disubstituted indole core structure 3 (Scheme 1). The requisite orthoalkenyl isocyanide 4 would be prepared from the alkyne 5, which in turn could be accessed by Sonogashira coupling of the aromatic iodide 6 with the terminal alkyne 7. To enable synthesis of the target compounds with high enantiomeric purity, the alkyne 7 derived from the Garner aldehyde (8) [7] was employed as a latent amino acid unit to be incorporated into the diketopiperazine.Initially, we focused our efforts on the synthesis of the isocyanide 12 as a radical-cyclization precursor (Scheme 2). The alkyne 7 was prepared from 8 according to the known protocol [8] with a slight modification. After the Sonogashira coupling between 7 and 2-iodoformanilide (9), partial reduction of the triple bond was examined. Whereas the use of the Lindlar catalyst, Pd/C, nickel boride, [9] or diimide [10] resulted in no reaction or overreduction, treatment with Zn/LiCuBr 2 in ethanol [11] gave the desired product 11 along with the corresponding amine. The use of 2,2,2-trifluoroethanol [12] as the solvent suppressed the undesired solvolysis and improved the yield of 11 to 99 %. Subsequent dehydration with bis(trichloromethyl) carbonate (triphosgene) gave the ortho-alkenyl isocyanide 12 and thus set the stage for a radical-mediated cyclization.When isocyanide 12 thus obtained was subjected to our previously established radical-cyclization conditions,[5a] the desired 5-exo adduct 13 was obtained in moderate yield after acidic treatment with silica gel along with a considerable amount of products 14 and 15 of a 6-endo cyclizationcleavage process (Scheme 3). We were aware of the tendency of this imidoy...

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“…1,2-Dibromoethane is also a useful reagent for activating zinc. 2,3 This reagent can be used as a source of electrophilic bromine for bromination of carbanions, 4 and also acts as an alkylating agent with many enolates. 5 1,2-Dibromoethane is a precursor to numerous 1,2-disubstituted ethane derivatives, for example 1,2-ethanedithiol.…”

Section: Introductionmentioning

confidence: 99%

1,2-Dibromoethane - A Versatile Reagent in Organic Synthesis

Aluri¹

2008

Synlett

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This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research 1,2-Dibromoethane -A Versatile Reagent in Organic Synthesis Compiled by Bhaskar Reddy AluriBhaskar Reddy Aluri was born in Hyderabad, India in 1979. He obtained his B.Sc. from Sri Krishna Devaraya University and his M.Sc. in Chemistry from the University of Hyderabad. After working for a short time in industry (Dr. Reddy's R & D division, Hyderabad) he joined the research group of Prof. Dr. J. Heinicke at the EMA University of Greifswald in 2005 and is currently working towards his Ph.D. His main interests lie in Organic Synthesis, Organometallic Chemistry, and Catalysis.

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A Quick Procedure for the Partial Reduction of Triple Bonds

Cited by 47 publications

References 1 publication

Pheromone synthesis. Part 257: Synthesis of methyl (2E,4Z,7Z)-2,4,7-decatrienoate and methyl (E)-2,4,5-tetradecatrienoate, the pheromone components of the male dried bean beetle, Acanthoscelides obtectus (Say)

Pheromone synthesis. Part 257: Synthesis of methyl (2E,4Z,7Z)-2,4,7-decatrienoate and methyl (E)-2,4,5-tetradecatrienoate, the pheromone components of the male dried bean beetle, Acanthoscelides obtectus (Say)

Total Synthesis of Tryprostatins A and B

1,2-Dibromoethane - A Versatile Reagent in Organic Synthesis

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