N-Functionalized 1-Alkynylamides: New Building Blocks for Transition Metal Mediated Inter- and Intramolecular [2+2+1] Cycloadditions

Witulski, B.; Stengel, Thomas

doi:10.1002/(sici)1521-3773(19980302)37:4<489::aid-anie489>3.3.co;2-e

Cited by 129 publications

(24 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…serves both in masking a secondary amine and in tuning the electron density, and hence the reactivity, of the adjacent acetylene moiety. 1 These new building blocks for organic synthesis were designed with the goal of combining the richness and diversity of the chemical reactivity of a carbon-carbon triple bond with one of the most substantial functional groups in chemistry and biology: the amino function.…”

mentioning

confidence: 99%

“…Recently we described the synthesis of these novel acetylenes based on a two step sequence-ethynylation of secondary amides with trimethylsilylethynyl(phenyl)iodonium triflate 2 followed by desilylation with TBAF-and the use of the thus derived N-ethynylamides, whose reactivity differs significantly from those of regular ynamines, 3 in both the Pauson-Khand reaction 1 and in Rh I -catalysed cyclotrimerisations. 4 Given our interest in N-functionalised 1-alkynylamides as versatile building blocks for nitrogen-containing heterocycles, we considered the N-ethynylamides B derived from a-amino acids as even more attractive targets, because their application in transition metal mediated cycloadditions should allow the asymmetric formation of conformationally constrained amino acids 5 and the synthesis of novel proline derivatives that are closely related to the highly potent ACE (angiotensine converting enzyme) inhibitor Ramipril.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Stereospecific synthesis of chiral N-(ethynyl)allylglycines and their use in highly stereoselective intramolecular Pauson–Khand reactions

Witulski¹,

Gößmann²

1999

Chem. Commun.

Self Cite

View full text Add to dashboard Cite

mentioning

confidence: 99%

mentioning

confidence: 99%

Stereospecific synthesis of chiral N-(ethynyl)allylglycines and their use in highly stereoselective intramolecular Pauson–Khand reactions

Witulski¹,

Gößmann²

1999

Chem. Commun.

Self Cite

View full text Add to dashboard Cite

“…13 C NMR (CDCl 3 , 100 MHz) δ (ppm): 171.7, 100.3, 91.1, 80.6, 52.7, 31.3, 30.5, 28.0, 25.9, 16.3, -4.7. HRMS (ESI) m / z : calcd for C 10 H 15 N 3 NaO 2 [2M + Na] + , 441.2226; found, 441.2220 [ 40 ].…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Dense 1,2,3-Triazole Polymers Soluble in Common Organic Solvents

Yamasaki

Kamon

et al. 2021

Polymers

View full text Add to dashboard Cite

Aiming at synthesis of dense 1,2,3-triazole polymers soluble in common organic solvents, a new 3-azido-1-propyne derivative, i.e., t-butyl 4-azido-5-hexynoate (tBuAH), was synthesized and polymerized by copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and Huisgen cycloaddition (HC). CuAAC polymerization produced poly(tBuAH) composed of 1,4-disubstituted 1,2,3-triazole units (1,4-units), whereas HC polymerization gave poly(tBuAH) composed of 1,4- and 1,5-disubstituted 1,2,3-triazole units (1,4- and 1,5-units). In HC polymerization, the fraction of 1,4-unit (f1,4) decreased with the permittivity of solvent used. Differential scanning calorimetry data indicated that the melting point of poly(tBuAH) increased from 61 to 89 °C with increasing f1,4 from 0.38 to 1.0, indicative of higher crystallinity of poly(tBuAH) composed of 1,4-unit. Preliminary steady-state fluorescence study indicated that all the poly(tBuAH) samples of different f1,4 emitted weak but significant fluorescence in DMF. The maximum of fluorescence band shifted from ca. 350 to ca. 450 nm with varying the excitation wavelength from 300 to 400 nm.

show abstract

“…Major strategies towards 3-oxygenated carbazole alkaloids Some years ago we established the first reliable synthesis of functionalized ynamides applying alkynyl iodonium salts as N-ethynylation reagents. 26 The use of ynamides as novel building blocks and synthons in combination with transition metal catalyzed reactions opened new pathways towards N-heterocycles as being demonstrated by us 27 and others. 28 However so far, the potential use of ynamides in total synthesis has been scarcely explored.…”

Section: Figure 1 Selected Naturally Occurring 3-oxygenated Carbazolesmentioning

confidence: 97%

Rhodium-Catalyzed Crossed [2+2+2] Cycloaddition with Ynamides: Key-Strategy for the Concise Total Synthesis of 3-Oxygenated Carbazole Alkaloids

Witulski¹,

Alayrac²

2021

HETEROCYCLES

Self Cite

View full text Add to dashboard Cite

Total syntheses of a set of naturally occurring 3-oxygenated carbazole alkaloids -6-chlorohyellazole, carazostatin, carbazomycins A and B -are described. The key-strategy underlines a highly chemo-and regioselective rhodium-catalyzed [2+2+2] cyclotrimerization between appropriately tailored yne-ynamides and 1-methoxypropyne that is stirred by the interplay o f stereoelectronic and steric effects allowing the introduction of four rin g substituents of the natural carbazoles within a single step and making the overall syntheses short and efficient.Carbazole alkaloids are an important class of natural products displaying high diversity in their substitution pattern and revealing a broad range of biological activities. 1 In the case of 3-hydroxycarbazole alkaloids, an alkyl chain is typically displayed at position C-1 but some exceptions are found. For example, hyellazole and 6-chlorohyellazole have the particularity of bearing a phenyl group at this position (Figure 1). Both are of marine origin and have been isolated from the blue-green alga Hyella caespitosa. 2 Other 3-hydroxycarbazoles such as antiostatin A1, 3 carazostatin, 4 and the carbazomycins 5 A and B were isolated from micro-organisms, Streptomyces cyaneus 2007-SV1, Streptomyces chromofuscus, and Streptoverticillium ehimense H1051-MY 10, respectively.Very recently, the carbazomycin B producing strain Streptomyces luteoverticillatus SZJ61 was isolated from marine sediment in China. 6 Carbazomycins A and B are the first carbazole-related antibiotics possessing weak antibacterial and antiyeast activity and inhibit the growth of some phytopathogenic fungi. 5a,6 Carbazomycin A displays weak cytotoxicity against cancerous (MCF-7, KB, NCI-H187) and non-

show abstract

N-Functionalized 1-Alkynylamides: New Building Blocks for Transition Metal Mediated Inter- and Intramolecular [2+2+1] Cycloadditions

Cited by 129 publications

References 0 publications

Stereospecific synthesis of chiral N-(ethynyl)allylglycines and their use in highly stereoselective intramolecular Pauson–Khand reactions

Stereospecific synthesis of chiral N-(ethynyl)allylglycines and their use in highly stereoselective intramolecular Pauson–Khand reactions

Synthesis of Dense 1,2,3-Triazole Polymers Soluble in Common Organic Solvents

Rhodium-Catalyzed Crossed [2+2+2] Cycloaddition with Ynamides: Key-Strategy for the Concise Total Synthesis of 3-Oxygenated Carbazole Alkaloids

Contact Info

Product

Resources

About