5233-99-8Relevant articles and documents
PHOTOAFFINITY LABELS FOR INSECT JUVENILE HORMONE BINDING PROTEINS SYNTHESIS AND EVALUATION IN VITRO
Prestwich, Glenn D.,Singh, Ambarish K.,Carvalho, Joan F.,Koeppe, John K.,Kovalick, Gae E.,Chang, Ernest S.
, p. 529 - 537 (1984)
The interactions of insect juvenile hormones (JH) with proteins are critically important to titer regulation, transport, and hormone action at a molecular level.We have synthesized several JH analogs bearing photolabile diazocarbonyl groups as potential photoaffinity labels for JH binding proteins (JHBP).The most promising compound, 10, 11-epoxyfarnesyl diazoacetate (2) (EFDA) competes with JH III for the JH binding site of JHBP from Leucophaea hemolymph and ovaries and from cultured Drosophila cells.Moreover, irradiation of protein solutions containing micromolar amounts of EFDA gave irreversible loss of -JH III binding capacity with no change in binding affinity of the unlabelled protein.The protein could be protected against photoinactivation by the presence of equimolar JH III during irradiation.High specific activity -EFDA was prepared and used to demonstrate specific, finite binding of EFDA to the JH III receptor site of the binding protein.Further applications of photoaffinity labelling technique to characterization and cellular localization of the JHBP are discussed.
Organocatalytic epoxidation and allylic oxidation of alkenes by molecular oxygen
Orfanidou, Maria,Petsi, Marina,Zografos, Alexandros L.
supporting information, p. 9172 - 9178 (2021/11/30)
Pyrrole-proline diketopiperazine (DKP) acts as an efficient mediator for the reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols was achieved by adding a catalytic amount of selenium dioxide as an additive, revealing a superior method to the classical application of t-BuOOH as a selenium dioxide oxidant.
Enantioselective Total Synthesis of Berkeleyone A and Preaustinoids
Franzoni, Ivan,Guo, Chuning,Hong, Benke,Ji, Yunpeng,Jia, Hongli,Li, Houhua,Zhang, Yang
supporting information, p. 14869 - 14874 (2021/05/27)
Herein we report the first enantioselective total synthesis of 3,5-dimethylorsellinic acid-derived meroterpenoids (?)-berkeleyone A and its five congeners ((?)-preaustinoids A, A1, B, B1, and B2) in 12–15 steps, starting from commercially available 2,4,6-trihydroxybenzoic acid hydrate. Based upon the recognition of latent symmetry within D-ring, our convergent synthesis features two critical reactions: 1) a symmetry-breaking, diastereoselective dearomative alkylation to assemble the entire carbon core, and 2) a Sc(OTf)3-mediated sequential Krapcho dealkoxycarbonylation/carbonyl α-tert-alkylation to forge the intricate bicyclo[3.3.1]nonane framework. We also conducted our preliminary biomimetic investigations and uncovered a series of rearrangements (α-ketol, α-hydroxyl-β-diketone, etc.) responsible for the biomimetic diversification of (?)-berkeleyone A into its five preaustinoid congeners.
Relay Cross Metathesis for the Iterative Construction of Terpenoids and Synthesis of a Diterpene-Benzoate Macrolide of Biogenetic Relevance to the Bromophycolides
Bahou, Karim A.,Braddock, D. Christopher,Meyer, Adam G.,Savage, G. Paul
supporting information, p. 3176 - 3179 (2020/04/15)
We report a relay cross metathesis (ReXM) reaction for the construction of terpenoids in an iterative protocol. The protocol features the cross metathesis of a relay-actuated Δ6,7-functionalized C10-monoterpenoid alcohol with C10-monoterpenoid citral to form a C15-sesquiterpene. Subsequent functional group manipulation allows for the method to be repeated in an iterative fashion. The method is used for the synthesis of a diterpene-benzoate macrolide of biogenetic relevance to the bromophycolide family of natural products.
Combinatorial evolution of site- and enantioselective catalysts for polyene epoxidation
Lichtor, Phillip A.,Miller, Scott J.
, p. 990 - 995 (2013/02/25)
Selectivity in the catalytic functionalization of complex molecules is a major challenge in chemical synthesis. The problem is magnified when there are several possible stereochemical outcomes and when similar functional groups occur repeatedly within the same molecule. Selective polyene oxidation provides an archetypical example of this challenge. Historically, enzymatic catalysis has provided the only precedents. Although non-enzymatic catalysts that meet some of these challenges became known, a comprehensive solution has remained elusive. Here, we describe low molecular weight peptide-based catalysts, discovered through a combinatorial synthesis and screening protocol, that exhibit site- and enantioselective oxidation of certain positions of various isoprenols. This diversity-based approach, which exhibits features reminiscent of the directed evolution of enzymes, delivers catalysts that compare favourably to the state-of-the-art for the asymmetric oxidation of these compounds. Moreover, the approach culminated in catalysts that exhibit alternative-site selectivity in comparison to oxidation catalysts previously described.
Biomimetic cyclization of epoxide precursors of indole mono-, sesquiand diterpene alkaloids by lewis acids
Isaka, Tetsuya,Hasegawa, Morifumi,Toshima, Hiroaki
experimental part, p. 2213 - 2222 (2012/02/14)
Cyclization of the synthesized epoxide precursors of indole mono-, sesqui- and diterpene alkaloids was performed to elucidate the mechanism for biomimetic cationic cyclization to polycyclic structures. 3-(6,7- Epoxygeranyl)indole (11), 3-(10,11-epoxyfarne
Rapid and enantioselective synthetic approaches to germanicol and other pentacyclic triterpenes
Surendra, Karavadhi,Corey
supporting information; experimental part, p. 8865 - 8869 (2009/02/03)
Two exceedingly short synthetic routes to the key intermediate 2 for the synthesis of the pentacyclic triterpene germanicol 1 have been developed. In the first, the (S)-epoxide of farnesyl bromide is transformed in just three steps to the tetracyclic intermediate 7, which is converted to chiral 2 by treatment with polyphosphoric acid. The second synthetic route to 2 involves the coupling of the (S)-epoxide 8 with vinyl iodide 9 to give 10 and two-stage acid-catalyzed cyclization of 10 to form 2. During the course of this work we have also discovered a very unusual intramolecular 1,5-proton shift from a carbocation to a C-C double bond. The details of the process have been confirmed by 2H-labeling experiments.
Farnesyl diphosphate analogues with ω-bioorthogonal azide and alkyne functional groups for protein farnesyl transferase-catalyzed ligation reactions
Labadie, Guillermo R.,Viswanathan, Rajesh,Poulter, C. Dale
, p. 9291 - 9297 (2008/03/14)
(Chemical Equation Presented) Eleven farnesyl diphosphate analogues, which contained ω-azide or alkyne substituents suitable for bioorthogonal Staudinger and Huisgen [3 + 2] cycloaddition coupling reactions, were synthesized. The analogues were evaluated
Catalytic diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups
Uyanik, Muhammet,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5649 - 5652 (2007/10/03)
Highly diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups was catalyzed by tin(IV) chloride (10 mol %). The cyclizations of tert-butyldiphenylsilyl and triisopropylsilyl polyenol ethers gave 4α(equatorial)- and 4β(axial)-siloxypolycycles as major isomers, respectively. The strong nucleophilicity of pro-C(9), a (6E) geometry, and a bulky silyl group effectively favored the 4α-preference, whereas the weak nucleophilicity of pro-C(9), a (6Z)-geometry, and less steric hindrance of a silyl group favored the 4β-preference.
Concise total syntheses of palominol, dolabellatrienone, β-araneosene, and isoedunol via an enantioselective Diels-Alder macrobicyclization
Snyder, Scott A.,Corey
, p. 740 - 742 (2007/10/03)
Concise total syntheses of four members of the dolabellane family of diterpenoid natural products are reported. Key features of the developed route include the first demonstration of an enantioselective, intramolecular Type I Diels-Alder macrobicyclization, the first example of a stereoselective π-allyl Stille coupling reaction involving a farnesyl-derived intermediate, a powerful new reagent for the formation of dithianes with acid-sensitive molecules, and a unique and highly efficient ring-contraction sequence based on a modified Wolff photochemical rearrangement. Copyright
