- Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
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Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
- Luo, Xiaosheng,Wang, Ping
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p. 4960 - 4965
(2021/07/20)
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- Proteome-wide mapping of PQS-interacting proteins in: Pseudomonas aeruginosa
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The opportunistic human pathogen Pseudomonas aeruginosa secretes 2-heptyl-3-hydroxy-4-quinolone (PQS), a quorum sensing (QS) signal that regulates the expression of numerous virulence genes. Here we report the development and application of chemical probes to globally map quinolone binding proteins. The revealed quinolone interactome contains both known as well as newly identified virulence factors and presents new targets for the treatment of bacterial infections.
- Dandela, Rambabu,Mantin, Danielle,Cravatt, Benjamin F.,Rayo, Josep,Meijler, Michael M.
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p. 2290 - 2294
(2018/03/05)
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- Intramolecular anti-Phosphinoauration of Alkynes: An FLP-Motivated Approach to Stable Aurated Phosphindolium Complexes
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The synthesis of aurated phosphindolium complexes from easy accessible 1,5-alkynylphosphine derivatives has been studied by using gold(I) complexes featuring carbene and phosphine ligands as initiators. Upon formation of the mixed phosphine NHC/phosphine
- Arndt, Sebastian,Hansmann, Max M.,Motloch, Petr,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 2542 - 2547
(2017/03/06)
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- Identifying Glyceraldehyde 3-Phosphate Dehydrogenase as a Cyclic Adenosine Diphosphoribose Binding Protein by Photoaffinity Protein-Ligand Labeling Approach
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Cyclic adenosine diphosphoribose (cADPR), an endogenous nucleotide derived from nicotinamide adenine dinucleotide (NAD+), mobilizes Ca2+ release from endoplasmic reticulum (ER) via ryanodine receptors (RyRs), yet the bridging protein(s) between cADPR and RyRs remain(s) unknown. Here we synthesized a novel photoaffinity labeling (PAL) cADPR agonist, PAL-cIDPRE, and subsequently applied it to purify its binding proteins in human Jurkat T cells. We identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as one of the cADPR binding protein(s), characterized the binding affinity between cADPR and GAPDH in vitro by surface plasmon resonance (SPR) assay, and mapped cADPR's binding sites in GAPDH. We further demonstrated that cADPR induces the transient interaction between GAPDH and RyRs in vivo and that GAPDH knockdown abolished cADPR-induced Ca2+ release. However, GAPDH did not catalyze cADPR into any other known or novel compound(s). In summary, our data clearly indicate that GAPDH is the long-sought-after cADPR binding protein and is required for cADPR-mediated Ca2+ mobilization from ER via RyRs.
- Zhang, Kehui,Sun, Wei,Huang, Linong,Zhu, Kaiyuan,Pei, Fen,Zhu, Longchao,Wang, Qian,Lu, Yingying,Zhang, Hongmin,Jin, Hongwei,Zhang, Li-He,Zhang, Liangren,Yue, Jianbo
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p. 156 - 170
(2017/05/16)
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- Zinc-catalyzed silylation of terminal alkynes
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(Chemical Equation Presented) A rapid and high-yielding silylation of terminal alkynes employing TMSOTf and catalytic quantities of Zn(OTf) 2 has been developed. The reaction works well for a variety of substrates including reactive esters. Fifteen examples with yields of >90% are reported.
- Rahaim Jr., Ronald J.,Shaw, Jared T.
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p. 2912 - 2915
(2008/09/19)
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- The difference in reactivity of (-)-mono and dimenthyl vs. diethyl alkylphosphonates in the α-lithiation reaction: Carbanionic synthesis of unknown (-)-dimenthyl 1-iodoalkylphosphonates and their first use in the radical iodine atom transfer addition (I-A
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Unknown (-)-dimenthyl and ethyl (-)-menthyl 1-iodoethylphosphonates were synthesized via 1-lithio derivatives in 85-87% yields. Starting (-)-dimenthyl alkylphosphonates (R = Me, Et, i-Pr) were obtained in the Michaelis-Becker reaction (75-81% yields) and/
- Ba?czewski, Piotr,Szadowiak, Aldona,Bodzioch, Agnieszka,Bia?as, Tomasz,Wieczorek, Wanda M.,Szyrej, Ma?gorzata
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p. 997 - 1009
(2007/10/03)
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- Facile hydroboration of (Z)-1-trimethylsilyl-1-alkenes with dichloroborane-dioxane complex: An easy access to gem-dimetalloalkanes containing boron and silicon
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(Z)-1-trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dichloroborane-dioxane complex in dichloromethane for 6 h. The resulting solution is then treated with 1,3-propane diol in dichloromethane at 0 °C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These α- trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing α-trimethylsilyl group in 78-88% isolated yields.
- Bhat, Narayan G.,Villanueva, Mary A.
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p. 1298 - 1300
(2007/10/03)
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- Endohedral metallocenophanes of rhodium and cobalt
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The synthesis of seven endohedral metallocenophanes of rhodium (7b, 8b) and cobalt (1d-h) with a cyclopentadienyl unit as one of the π-systems and a cyclobutadiene or cyclopentadienone unit as the second π-system is described, including the synthesis of the unsubstituted parent compound of the [CpCo(cbd)]-derived endohedral phanes, [3.3]-η5-(1,1′,3, 3′)-cyclopentadienyl-η4-(cyclobutadienophane)cobalt(I) (1h). This compound could be obtained by deprotection of the corresponding trimethylsilyl-substituted endohedral phane 1g. The X-ray structures of 7b, 1e, 1g and 1h could be obtained. This paper compares their structural properties to the complexes reported in previous short communications.
- Schaefer, Carsten,Scholz, Gerald,Gleiter, Rolf,Oeser, Thomas,Rominger, Frank
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p. 1274 - 1281
(2007/10/03)
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- A simple synthesis of B-2-(1-trimethylsilyl-1-alkyl)-1,3,2-dioxaborinanes. Isolation and selective oxidation to 1-trimethylsilyl-1-alkanols
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(Z)-1-Trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dibromoborane-methyl sulfide complex in dichloromethane for 6 h. The resulting solution is then treated with 1, 3-propane diol in a 1:1 mixture of dichloromethane and n-pentane at 0°C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These alpha-trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing trimethylsilyl group.
- Bhat, Narayan G.,Garza, Amanda
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p. 6833 - 6835
(2007/10/03)
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- The scope of catalytic enantioselective tandem carbonyl ylide formation - Intramolecular [3 + 2] cycloadditions
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Catalytic enantioselective tandem carbonyl ylide formation-intramolecular 1,3-dipolar cycloaddition reactions of 2-diazo-3,6-diketoesters show promising scope in terms of asymmetric induction as the tethered alkene/alkyne dipolarophile component is varied. Cycloadditions were found to occur in moderate to very good yields, with a difference in ee exhibited by the electronically different 2-diazo-3,6-diketoesters 1, 25 and 33, 34. Values for ee of up to 90% for alkene dipolarophiles and up to 86% for alkyne dipolarophiles were obtained.
- Hodgson, David M.,Labande, Agnes H.,Pierard, Francoise Y. T. M.,Exposito Castro, Maria A.
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p. 6153 - 6159
(2007/10/03)
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- Organocobaloximes in organic synthesis An unusual radical-dependent five-member cyclization
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Visible light photolysis of organocobaloximes R′C=C[CH2]3-CoIII(dmgH)2Py 1-3 (R′ = Ph, TMS, H) with radical trapping agents ArSO2Cl (Ar = Ph, 4-MeC6H4, 4-OMeC6H4
- Das, Indira,Chowdhury, Shantanu,Ravikumar, Krishnan,Roy, Sujit,Gupta, Bhagawan Dass
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p. 101 - 107
(2007/10/03)
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- A convenient synthesis of alkynylsilanes by silylation of copper(I) alkynides
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Alkynylation of chlorosilanes with copper(I) alkynides takes place smoothly in the presence of triphenylphosphine, N, N, N′, N′-tetramethylethylenediamine, or zinc powder to give a variety of alkynylsilanes in good yields.
- Sugita, Hikaru,Hatanaka, Yasuo,Hiyama, Tamejiro
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p. 379 - 380
(2007/10/03)
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- Organolanthanide-catalyzed intramolecular hydroamination/cyclization of aminoalkynes
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This contribution reports the efficient and regiospecific Cp'2LnCH(SiMe3)2 (Ln = La, Nd, Sm, Lu; Cp' = η5-Me5C5)- and Me2SiCp''2LnCH(SiMe3)2 (Ln = Nd, Sm; Cp'' = η5-Me4C5)-catalyzed hydroamination/cyclization of aliphatic and aromatic aminoalkynes of the formula RC≡C(CH2)(n)NH2 to yield the corresponding cyclic imines RCH2C=N(CH2)(n-1)CH2, where R, n, N(t) h-1 (°C) = Ph, 3, 77 (21°C); Ph, 3, 2830 (60°C); Me, 3, 96 (21°C); CH2=CMeCH2, 3, 20 (21°C); H, 3, 580 (21°C); Ph, 4, 4 (21°C); Ph, 4, 328 (60°C); Ph, 5, 0.11 (60°C); and SiMe3, 3, >7600 (21°C), and of aliphatic secondary amino-alkynes of the formula RC≡C(CH2)3NHR1 to generate the corresponding cyclic enamines RCH=CNR1(CH2)2CH2 where R, R1, N(t) h-1 (°C) = SiMe3, CH2=CHCH2, 56 (21°C); H, CH2=CHCH2, 27 (21°C); SiMe3, CH2=CH(CH2)3, 129 (21°C); and H, CH2=CH(CH2)3, 47 (21°C). Kinetic and mechanistic evidence is presented arguing that the turnover-limiting step is an intramolecular alkyne insertion into the Ln-N bond followed by rapid protonolysis of the resulting Ln-C bond. The use of larger metal ionic radius Cp'2LnCH(SiMe3)2 and more open Me2SiCp''2LnCH(SiMe3)2 complexes as the precatalysts results in a decrease in the rate of hydroamination/cyclization, arguing that the steric demands in the -C≡C- insertive transition state are relaxed compared to those of the analogous aminoolefin hydroamination/cyclization.
- Li,Marks
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p. 9295 - 9306
(2007/10/03)
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- Silylation of 1-Alkynes with Chlorosilanes Promoted by Zinc: Preparation of Alkynylsilanes in a Single Step
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The direct silylation of 1-alkynes with chlorosilanes smoothly takes place in the presence of zinc powder in acetonitrile, giving good yields of alkynylsilanes.The reactions are tolerant of a wide range of functionalities such as carboxylic acid, ester, alcohol, and chlorine in the 1-alkynes.
- Sugita, Hikaru,Hatanaka, Yasuo,Hiyama, Tamejiro
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p. 2769 - 2772
(2007/10/02)
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- Versatile syntheses of alkynyl- and substituted alkynylcyclopropanes: 2-Alkoxyethynylcyclopropanes for the anellation of bicyclo[3.3.0]octane fragments
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Enol ethers 1a-f are brominated at -78°C and the resulting alkyl 1,2-dibromoethyl ethers are regioselectively coupled with propargylmagnesium bromide to give 4-alkoxy-5-bromo-1-pentynes 2a-f, which are protected at the acetylenic terminus with a trimethylsilyl group. These 4-alkoxy-5-bromo-1-trimethylsilyl-1-pentynes 3a-f readily cyclize by γ-elimination to give trimethylsilyl protected 2-alkoxyethynylcyclopropanes 4a-f in excellent overall yields. Under appropriate conditions (E)-diastereomers (E)-4a-f can be prepared selectively. The diastereoselectivity of the bromine addition onto enantiomerically pure chiral enol ethers 1e and 1f, however, is 64% (for 2f) at best. 2-Alkoxy-1-trimethylsilylethynylcyclopropanes(E/Z)-4 can be deprotonated with LDA or butyllithium to give configurationally stable 1-lithio derivatives (E)-6, which are trapped by reactive electrophiles (protons, carbonyl compounds, tosyl halides) with retention of configuration on the three-membered ring. 2-Alkoxy-1-ethynylcyclopropanes 5 can be used to anellate a bicyclo[3.3.0]octane fragment onto a cycloalkene in a domino-type reaction sequence, as demonstrated by the Pauson-Khand cycloaddition of(E)-5c to norbornene (14) as well as deltacyclene (20), and subsequent interconversion to the tetracyclic and hexacyclic compounds anti/syn-19 and anti/syn-25/27 with a reasonable degree of diastereoselectivity.
- Militzer,Schomenauer,Otte,Puls,Hain,Brase,De Meijere
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p. 998 - 1012
(2007/10/02)
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- Pesticidal compounds
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The present invention provides a class of novel substituted bicyclooctanes which have pesticidal activity, particularly against arthropod pests. Pesticidal formulations containing the compounds of the formula (I), their use in the control of pests and methods for their preparation are also disclosed.
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- The synthesis of (E)-arylidene and allylidene cyclopentanes by means of a pallodium(0)-catalyzed complex
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When treated with an unsaturated halide in a palladium-catalyzed process, the anions from γ-acetylenic malonates 4 and 5 stereospecifically lead to cyclopentanes having an exo tri- or tetra-substituted double bond. This reaction which forms simultaneously two carbon-carbon bonds is believed to proceed by nucleophilic attack of the anion on the triple bond activated by the σ-aryl or σ-vinyl palladium complex.
- Fournet,Balme,Gore
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p. 6293 - 6304
(2007/10/02)
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- Simple preparation of α-bromo acyl silanes α-ketoacyl silanes and α-ketoesters from silyl acetylenes
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α-Bromo- and α-keto-acyl silanes may simply and efficiently be prepared in short reaction schemes from silyl acetylenes; α-ketoacyl silanes are also implicated in a one-pot synthesis of α-ketoesters from silyl acetylenes.
- Bulman Page, Philip C.,Rosenthal, Stephen
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p. 2573 - 2586
(2007/10/02)
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- Intramolecular Photochemical Cycloadditions. 3. Perhydrohistrionicotoxin Synthetic Studies: Synthesis of Spirodecanones via Intramolecular Photocycloaddition
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We describe here a full account of our efforts directed toward the synthesis of 4, a known intermediate in the synthsis of perhydrohistrionicotoxin (2).Irradiation of 7 followed by oxidative cleavage of the derived cyclobutene 6 produced 5 or 11, depending on the method of cyclobutene cleavage.While 5 could not be decarboxylated with (Ph3P)3RhCl, thermal decarboxylation of 11 furnished 12a and 12b with the undesired stereochemistry at C(6) predominating, vis a vis perhydrohistrionicotoxin.Thus, while this strategy does not appear to be viable for perhydrohistrionicotoxin, the photocycloaddition cyclobutene cleavage sequence constitutes a valuable method for the rapid construction of the spirodecanone ring system with a high degree of stereocontrol.
- Koft, Emil R.,Smith, Amos B.
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p. 832 - 836
(2007/10/02)
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