- Asymmetric Cation-Olefin Monocyclization by Engineered Squalene–Hopene Cyclases
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Squalene–hopene cyclases (SHCs) have great potential for the industrial synthesis of enantiopure cyclic terpenoids. A limitation of SHC catalysis has been the enzymes’ strict (S)-enantioselectivity at the stereocenter formed after the first cyclization step. To gain enantio-complementary access to valuable monocyclic terpenoids, an SHC-wild-type library including 18 novel homologs was set up. A previously not described SHC (AciSHC) was found to synthesize small amounts of monocyclic (R)-γ-dihydroionone from (E/Z)-geranylacetone. Using enzyme and process optimization, the conversion to the desired product was increased to 79 %. Notably, analyzed AciSHC variants could finely differentiate between the geometric geranylacetone isomers: While the (Z)-isomer yielded the desired monocyclic (R)-γ-dihydroionone (>99 % ee), the (E)-isomer was converted to the (S,S)-bicyclic ether (>95 % ee). Applying the knowledge gained from the observed stereodivergent and enantioselective transformations to an additional SHC-substrate pair, access to the complementary (S)-γ-dihydroionone (>99.9 % ee) could be obtained.
- Aeberli, Natalie,Berweger, Raphael,Bornscheuer, Uwe T.,Buller, Rebecca,Dossenbach, Sandro,Eichenberger, Michael,Eichhorn, Eric,Flachsmann, Felix,Hüppi, Sean,Hortencio, Lucas,Patsch, David,Voirol, Francis,Vollenweider, Sabine
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p. 26080 - 26086
(2021/09/20)
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- Adult Monochamus alternatus attractant and preparation method thereof
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The invention discloses an adult Monochamus alternatus attractant and a preparation method thereof, and belongs to the technical field of insect attractant production. The main effective component ofthe adult Monochamus alternatus attractant is an artificially synthesized compound having a high attracting effect on Monochamus alternatus, and comprises a botanical compound and a diluent. The attractant has the advantages of reasonability in proportioning and high trapping efficiency, and can efficiently monitor, trap and kill adult Monochamus alternatus. The invention also provides a synthesisroute and the synthesis method of the artificially synthesized compound with the high attracting effect on Monochamus alternatus. The adult Monochamus alternatus attractant is prepared from geranylacetone, a reducing agent and acetyl chloride. The method has the advantages of simple raw materials, environmentally friendly steps, high production efficiency and good industrial application prospect,can be used for preparing the adult Monochamus alternatus attractant on a large scale, and has high practical application values.
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Paragraph 0025-0034
(2020/02/29)
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- Enantioselective synthesis and absolute configuration of the sex pheromone of Hedypathes betulinus (Coleoptera: Cerambycidae)
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The male-produced sex pheromone of Hedypathes betulinus was identified as a mixture of (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone) (1) and its respective alcohol (2) and acetate (3). Kinetic resolution of alcohol (2) promoted by CAL-B in organic media provided both, (R)-(-)-(E)-6,10-dimethyl-5,9- undecadien-2-yl acetate (3) and (S)-(+)-(E)-6,10-dimethyl-5,9-undecadien-2-ol (2) in high enantiomeric purity. Comparative GC analysis using a chiral column revealed the natural constituents as being (R)-(3) and a mixture of (R)- and (S)-(2) in a ratio of 82.3% and 17.6%, respectively.
- Vidal, Diogo M.,Fonseca, Marcy G.,Zarbin, Paulo H.G.
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supporting information; experimental part
p. 6704 - 6706
(2011/02/23)
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- First total synthesis of (±) Hedaol B
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Hedaol B, a new bisnorditerpene isolated from the Japanese brown alga Sargassum. sp., was first synthesized starting from geranyl acetone, alkylation of silyl cyanide as the key step.
- Li, Ying,Lu, Biao,Li, Chunhong,Li, Yulin
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p. 1417 - 1423
(2007/10/03)
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