- Combining two-directional synthesis and tandem reactions: A short formal synthesis of halichlorine
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A short and efficient synthesis of an advanced intermediate (1) in the Clive route to halichlorine has been achieved in 12 steps and 13.2% yield by a combined two-directional synthesis/tandem reaction strategy.
- Gignoux, Camille,Newton, Annabella F.,Barthelme, Alexandre,Lewis, William,Alcaraz, Marie-Lyne,Stockman, Robert A.
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- Practical synthesis of Z-unsaturated esters by using a new Horner-Emmons reagent, ethyl diphenylphosphonoacetate
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A new Horner-Emmons reagent, ethyl diphenylphosphonoacetate 1 was prepared from triethyl phosphonoacetate, PCl5, and phenol in 60% overall yield. Horner-Emmons reaction of 1 with aldehydes in the presence of Triton B or NaH in THF gave the Z-unsaturated esters in 89-93% selectivity in almost quantitative yields. Furthermore, 1 showed up to 99% Z-selectivity under Still's condition (KHMDS/18-crown-6).
- Ando, Kaori
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- Detection of a New Piperideine Alkaloid in the Pygidial Glands of Some Stenus Beetles
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Rove beetles of the genus Stenus produce and store bioactive alkaloids like stenusine (3), 3-(2-methylbut-1-enyl)pyridine (4), and cicindeloine (5) in their pygidial glands to protect themselves from predation and microorganismic infestation. The biosynth
- Wittmann, Isabel,Schierling, Andreas,Dettner, Konrad,G?hl, Matthias,Schmidt, Jürgen,Seifert, Karlheinz
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- A Straightforward, Purification-Free Procedure for the Synthesis of Ando and Still-Gennari Type Phosphonates
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Z-Selective Still-Gennari and Ando modifications of the typically E-selective Horner-Wadsworth-Emmons reaction are highly valuable synthetic tools in organic chemistry. These procedures are based on application of bis(2,2,2-trifluoroethyl) phosphonates or diaryl phosphonates, respectively, for the olefination of carbonyl groups. In our research, we present an improved, straightforward, purificationfree procedure for the synthesis of these reagents. The key step of our procedure is the reaction of phosphonic dichlorides with the appropriate sodium alkoxides, which results in 52-97% isolated yields of the desired products on a gram scale. The whole three-step process is performed in one pot. Most importantly, the product is obtained in over 95% purity after simple extraction, avoiding column chromatography and distillation. Moreover, we present the synthesis of a novel Still-Gennari type reagent, bis(1,1,1,3,3,3-hexafluoroisopropyl) phosphonates, which may exhibit improved Z-selectivity in Still-Gennari olefinations.
- Janicki, Ignacy,Kie?basiński, Piotr
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p. 378 - 382
(2021/10/21)
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- Intramolecular Pd-Catalyzed Arylation of 1-Amidosugars: A New Route to N-Glycosyl Quinolin-2-ones
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The synthesis of N-glycosylated quinolin-2-ones via an intramolecular N-arylation of glycosylamides is reported. The coupling involves the use of only Pd(OAc)2 as the catalyst and nBu4NOAc as the base in 1,4-dioxane. This versatile approach allows the synthesis of various N-glycosylated quinolin-2-ones with exclusive α or β selectivity.
- Luong, Thi Thanh Huyen,Brion, Jean-Daniel,Lescop, Ewen,Alami, Mouad,Messaoudi, Samir
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supporting information
p. 2126 - 2129
(2016/06/01)
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- Assembly of indenamine derivatives through in situ formed N-sulfonyliminium ion initiated cyclization
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An expedient route to structurally diverse indenamine derivatives through condensation of the readily accessible substituted cinnamylaldehydes and sulfonylamines under the catalysis of FeCl3 has been developed, featuring high efficiency in the generation of two bonds and one ring in a single-step and water as the only by-product. This journal is the Partner Organisations 2014.
- Fan, Xiaohui,Lv, Hao,Guan, Yong-Hong,Zhu, Hong-Bo,Cui, Xiao-Meng,Guo, Kun
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supporting information
p. 4119 - 4122
(2014/04/03)
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- Cis-specific hydrofluorination of alkenylarenes under palladium catalysis through an ionic pathway
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This paper describes the hydrofluorination of alkenes through sequential H- and F+ addition under palladium catalysis. The reaction is cis specific, thus providing access to benzylic fluorides. The mechanism of this reaction involves an ionic pathway and is distinct from known hydrofluorinations involving radical intermediates. The first catalytic enantioselective hydrofluorination is also disclosed. See attached PdF: A series of benzylic fluorides was prepared by hydrofluorination which proceeds through a PdII/IV catalytic manifold. The method is mechanistically distinct from previously reported radical hydrofluorination, and is characterized by its clean regioselectivity and unique cis stereospecificity. The first example of enantioselective net HF addition onto 2-vinylnaphthalene is also disclosed.
- Emer, Enrico,Pfeifer, Lukas,Brown, John M.,Gouverneur, Veronique
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supporting information
p. 4181 - 4185
(2014/05/06)
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- Catalyst-controlled switchable phosphination of α-diazoesters
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Organocatalyst and metal provide different products: a catalyst-controlled switchable phosphination of α-diazoesters has been developed by using DBU and copper as catalysts. It provided an efficient synthetic method for the construction of various phospho
- Jiang, Honglai,Jin, Hongming,Abdukader, Ablimit,Lin, Aijun,Cheng, Yixiang,Zhu, Chengjian
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supporting information
p. 3612 - 3615
(2013/06/27)
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- Phosphonate modification for a highly (Z)-selective synthesis of unsaturated esters by Horner-Wadsworth-Emmons olefination
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The Horner-Wadsworth-Emmons (HWE) reaction of various ethyl diarylphosphonoacetates with benzaldehyde, cyclohexane carboxaldehyde and octanal is reported. Selectivities of up to 98% at -78°C are obtained with the three substrates. Among all the phosphonates prepared, the reagent based on 2-tert-butylphenol proved to be especially efficient, with Z/E ratios close to 95:5 at 0°C. It appears thus to be the reagent of choice for the (Z)-selective HWE reaction with both aromatic and aliphatic aldehydes. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Touchard, Francois P.
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p. 1790 - 1794
(2007/10/03)
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- Stereoselective preparation of (E)-α-bromoacrylates from mixtures of brominated ando phosphonates
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We prepared 69:31-11:89 mixtures of phosphonates 6b and 7b containing two phenoxy substituents, a CO2Et group, and 1 or 2 bromine atoms, respectively, at the interspersed methylene group. Deprotonating 64:36 mixtures of these reagents with NaH
- Olpp, Thomas,Brueckner, Reinhard
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p. 2135 - 2152
(2007/10/03)
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- Proton exchange and chemoselectivity in metal cation and hydroxide ion hydrolyses of phosphonoacetate diesters
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Phosphonoacetate diesters exhibit base catalyzed D/H proton exchange and C-OR esterolysis, as well as (acidic) hydrolyses mediated by Th4+ and Zr4+ ions.
- Moss, Robert A.,Gong, Paul K.
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p. 7845 - 7848
(2007/10/03)
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- Highly Selective Synthesis of Z-Unsaturated Esters by Using New Horner-Emmons Reagents, Ethyl (Diarylphosphono)acetates
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New Horner-Emmons reagents, ethyl (diarylphosphono)acetates 1, were prepared from triethyl phosphonoacetate, PCl5 the corresponding phenols. The reaction of 1 with several kinds of aldehydes in the presence of Triton B or NaH in THF solvent revealed that these reagents are useful for the synthesis of Z-unsaturated esters. Among the reagents examined, ethyl(di-o-tolylphosphono)-, [bis(o-ethylphenyl)phosphonol-, and [bis(o-isopropylphenyl)phosphono]acetates (1k-m) were found to be the most effective, giving Z-unsaturated esters with 93-99% selectivity.
- Ando, Kaori
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p. 1934 - 1939
(2007/10/03)
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