- Allenone-Mediated Racemization/Epimerization-Free Peptide Bond Formation and Its Application in Peptide Synthesis
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Allenone has been identified as a highly effective peptide coupling reagent for the first time. The peptide bond was formed with an α-carbonyl vinyl ester as the key intermediate, the formation and subsequent aminolysis of which proceed spontaneously in a racemization-/epimerization-free manner. The allenone coupling reagent not only is effective for the synthesis of simple amides and dipeptides but is also amenable to peptide fragment condensation and solid-phase peptide synthesis (SPPS). The robustness of the allenone-mediated peptide bond formation was showcased incisively by the synthesis of carfilzomib, which involved a rare racemization-/epimerization-free N to C peptide elongation strategy. Furthermore, the successful synthesis of the model difficult peptide ACP (65-74) on a solid support suggested that this method was compatible with SPPS. This method combines the advantages of conventional active esters and coupling reagents, while overcoming the disadvantages of both strategies. Thus, this allenone-mediated peptide bond formation strategy represents a disruptive innovation in peptide synthesis.
- Wang, Penghui,Wang, Xuewei,Wang, Zhengning,Zhao, Junfeng
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supporting information
p. 10374 - 10381
(2021/07/26)
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- Revisiting the Addition of in-situ Nucleophiles to Allenic Ketones: An Entry Towards Synthesis of Benzodioxins
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The manuscript delineates a revisit towards regioselective addition of in situ generated negative nucleophiles to allenic ketones in the presence of a base. A wide variety of allenic ketones as well as nucleophiles are viable in this transformation. A dir
- Sahoo, Sushree Ranjan,Sarkar, Debayan
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supporting information
p. 1727 - 1731
(2020/03/13)
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- Base-promoted direct synthesis of functionalized: N -arylindoles via the cascade reactions of allenic ketones with indoles
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A convenient Cs2CO3-promoted cascade benzannulation reaction of allenic ketones with indoles was achieved for the synthesis of functionalized N-arylindole derivatives under transition-metal-free conditions. A series of readily available starting materials can undergo the process successfully. It represents a practical method for the construction of N-arylindole scaffolds with high atom economy.
- Li, Shengxiao,Wu, Xin-Xing,Chen, Shufeng
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supporting information
p. 789 - 793
(2019/01/30)
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- Cycloisomerization of Conjugated Allenones into Furans under Mild Conditions Catalyzed by Ligandless Au Nanoparticles
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Au nanoparticles supported on TiO2 (1 mol %) catalyze the quantitative cycloisomerization of conjugated allenones into furans under very mild conditions. The reaction rate is accelerated by adding acetic acid (1 equiv), but the acid does not participate in the protodeauration step as in the corresponding Au(III)-catalyzed transformation. The process is purely heterogeneous, allowing thus the recycling and reuse of the catalyst effectively in several runs.
- Zorba, Leandros,Kidonakis, Marios,Saridakis, Iakovos,Stratakis, Manolis
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supporting information
p. 5552 - 5555
(2019/08/01)
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- Diverging Pathways in the Activation of Allenes with Lewis Acids and Bases: Addition, 1,2-Carboboration, and Cyclization
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The reactions of allenes with frustrated (or cooperative) Lewis acid/base pairs result in the 1,4-addition of the base pair to the allene. The reactions of allenyl ketones and esters just in the presence of the strong Lewis acid B(C6F5/su
- Melen, Rebecca L.,Wilkins, Lewis C.,Kariuki, Benson M.,Wadepohl, Hubert,Gade, Lutz H.,Hashmi, A. Stephen K.,Stephan, Douglas W.,Hansmann, Max M.
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supporting information
p. 4127 - 4137
(2015/09/01)
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- Synthesis of Acyl Alkenylindium Reagents and Their Application in the Synthesis of (Z)-α,β-Unsaturated Ketones via Palladium-Catalyzed Cross-Coupling Reaction
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A synthetic method for the preparation of acyl alkenylindium reagents was developed involving the hydroindation reaction of allenyl ketones with indium and indium chloride in methanol under mild conditions. Their synthetic applications were demonstrated from Pd-catalyzed cross-coupling reactions with aryl bromides and iodides and alkenyl and aryl triflates for the synthesis of (Z)-α,β-unsaturated ketones.
- Park, Youngchul,Min, Jiae,Eom, Dahan,Lee, Phil Ho
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supporting information
p. 3934 - 3937
(2015/08/19)
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- Room temperature Fe(NO3)3·9H 2O/TEMPO/NaCl-catalyzed aerobic oxidation of homopropargylic alcohols
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A practical and eco-friendly aerobic oxidation of homopropargylic alcohols using Fe(NO3)3·9H2O/TEMPO/NaCl as catalysts at room temperature under atmospheric pressure was developed affording corresponding homopropargylic ke
- Liu, Jinxian,Ma, Shengming
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p. 10161 - 10167
(2013/11/06)
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- Gold-catalyzed regioselective synthesis of 2- and 3-alkynyl furans
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Chemical Matching: C2- or C3-alkynylated furans were selectively synthesized by using gold catalysis. Direct C-H alkynylation of furans was achieved with C2 selectivity, and a domino cyclization/alkynylation process starting from allenes gave C3-alkynylat
- Li, Yifan,Brand, Jonathan P.,Waser, Jerome
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supporting information
p. 6743 - 6747
(2013/07/26)
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- Tandem reactions of 1,2-allenic ketones leading to substituted benzenes and α,β-unsaturated nitriles
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One-pot double Michael addition/intramolecular aldol reaction/ decarboxylation of 1,2-allenic ketones with cyanoacetate offers an efficient and convenient approach to highly functionalized benzenes. With 2-substituted cyanoacetates, the reaction proceeds via a different tandem process to afford α,β-unsaturated nitriles effectively.
- Zhang, Xinying,Jia, Xuefei,Fang, Liangliang,Liu, Nan,Wang, Jianji,Fan, Xuesen
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supporting information; experimental part
p. 5024 - 5027
(2011/11/12)
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- A halide-initiated aza-Baylis-Hillman reaction: Generation of unnatural amino acids
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A series of allenic ketones react with a glyoxylate-derived imine in the presence of MgBr2 through an aza-Morita-Baylis-Hillman (MBH) reaction. The isolation of a variety of unnatural amino acids with unique allene-containing functional groups
- Davis, Lindsey O.,Tobey, Suzanne L.
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supporting information; experimental part
p. 6078 - 6081
(2011/01/04)
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- The high stereoselective synthesis of β-alkynyl-enol phosphates
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A high stereoselective synthesis for β-alkynyl-enol phosphates from β-alkynyl ketone and dialkyl phosphite, via Atherton-Todd reaction, was reported. NaH as base gave a nearly pure Z-isomer.
- Ding,Huang
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p. 449 - 454
(2007/10/03)
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- Indium-mediated highly regioselective reaction of prop-2-ynyl bromides with acyl cyanides in aqueous media: A convenient synthesis of allenic and propargylic ketones
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Indium-mediated reaction of acyl cyanides 1 with prop-2-ynyl bromides 2 in aqueous media occurs regioselectively to afford either allenic 3 or propargylic ketones 4 depending on the γ-substituent of the prop-2-ynyl bromide under the mild conditions.
- Yoo, Byung-Woo,Lee, Sung-Jae,Choi, Kwang-Hyun,Keum, Sam-Rok,Ko, Jae-Jung,Choi, Kyung-Il,Kim, Joong-Hyup
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p. 7287 - 7289
(2007/10/03)
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- C-C-Bond Formation by the Palladium-Catalyzed Cycloisomerization/Dimerization of Terminal Allenyl Ketones: Selectivity and Mechanistic Aspects
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The scope of the palladium-catalyzed cyclization/dimerization of terminal allenyl ketones 1 to the 2,4-disubstituted furans 3 has been investigated. Simplified and improved conditions almost exclusively provided the dimer 3, accompanied by only traces of the easily separable monomer 2. The formation of an isomer of 3, the unconjugated ketone 4, was completeley suppressed. Under these mild conditions, besides the normal functional group tolerance known for palladium-catalyzed reactions, an interesting selectivity was observed with functional groups that are known to react either in palladium-catalyzed reactions or reactions catalyzed by other transition-metals. Thus aryl halides, terminal alkynes, 1,6-enynes, and α-allenic alcohols were tolerated. In the latter example the selective reaction of only one out of two different allenes was achieved. Mechanistic investigation indicated a Pd(II)/Pd(IV)-cycle involving palladium(II)-γ-alkoxyvinylcarbene and furylpalladium(IV) hydride intermediates, although a second pathway for the formation of the dimer 3 which also involves Pd(IV)-intermediates like the 3,4-dimethylenepalladacyclopentane 23 and the 3-methylenepalladacyclobutane-like structure 15 (respectively 25) could not completely be excluded.
- Hashmi, A. Stephen K.,Ruppert, Thorsten L.,Knoefel, Thomas,Bats, Jan W.
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p. 7295 - 7304
(2007/10/03)
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