ORCID Profile
0000-0001-9415-9917
Current Organisation
RWTH Aachen University
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Publisher: American Chemical Society (ACS)
Date: 18-05-2006
DOI: 10.1021/JO060668H
Abstract: Syntheses of three regioisomers of aromatic-substituted phosphinyl-oxazolinyl-[2.2]paracyclophanes, pseudo-geminal, pseudo-ortho, and ortho, have been carried out or, in the latter two cases, newly developed. It has, therefore, been demonstrated that all aromatic-substituted isomers relevant for use as chelating ligands for asymmetric catalysis are accessible. These P,N-ligands, along with their diastereoisomers, were shown to exhibit widely differing activity and enantioselectivity (up to 89% ee) in the Pd-catalyzed asymmetric allylic alkylation reaction.
Publisher: Wiley
Date: 16-05-2012
Publisher: Wiley
Date: 12-02-2013
Publisher: Wiley
Date: 17-05-2013
Publisher: Wiley
Date: 12-06-2023
Abstract: Sulfondiimines are marginalized entities among nitrogen‐containing organosulfur compounds, despite offering promising properties for applications in various fields including medicinal and agrochemical. Herein, we present a metal‐free and rapid synthetic procedure for the synthesis of N ‐monosubstituted sulfondiimines that overcomes current limitations in their synthetic accessibility. Particularly, S , S ‐dialkyl substrates, which are commonly difficult to convert by existing methods, react well with a combination of iodine, 1,8‐diazabicyclo[5.4.0]undec‐7‐en (DBU), and iminoiodinanes (PhINR) in acetonitrile (MeCN) to furnish the corresponding sulfondiimines in yields up to 85 % (25 ex les). Valuable “free” N H‐ N ′H‐sulfondiimines can then be accessed by N ‐deprotection under mild reaction conditions. Several experimental observations suggest a mechanistic pathway erging from the common radical‐based iodine/iminoiodinane mechanism. Based on the experimental results in combination with data obtained by 1 H NMR spectroscopy, ESI mass spectrometry, and crystallographic analysis we propose a direct amination from PhINNs and a reaction path via a cationic iodonitrene.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CS60185D
Abstract: Acylsilanes are a fascinating class of compounds that display a number of distinctive chemical and physical properties. The unique reactivity pattern of the acylsilane functional group [R-C(O)Si] makes them an increasingly attractive moiety in modern organic synthesis, and as such, they have been utilised in a erse range of transformations. This review provides an overview of the recent advances in the synthesis and application of acylsilanes in organic chemistry, with a particular focus on the progress made in the last two decades.
Publisher: Wiley
Date: 30-01-2007
Abstract: The initial steps of an enantioselective Diels-Alder reaction catalyzed by a CuII-bissulfoximine complex were followed by EXAFS (EXAFS=extended X-ray absorption fine structure), EPR (EPR=electron paramagnetic resonance) spectroscopy (CW-EPR, FID-detected EPR, pulse ENDOR, HYSCORE CW=continuous wave ENDOR=electron nuclear double resonance HYSCORE=hyperfine sublevel correlation FID=free induction decay), and UV-visible spectroscopy. The complexes formed between the parent CuX2 (X=Cl-, Br-, TfO-, SbF6-) salts, the chiral bissulfoximine ligand (S,S)-1, and N-(1-oxoprop-2-en-1-yl)oxazolidin-2-one (2) as the substrate in CH2Cl2 were investigated in frozen and fluid solution. In all cases, penta- or hexacoordinated CuII centers were established. The complexes with counterions indicating high stereoselectivity (TfO- and SbF6-) reveal one unique species in which substrate 2 binds to pseudoequatorial positions (via O atoms), shifting the counterions to axial locations. On the other hand, those lacking stereoselectivity (X=Cl- and Br-) form two species in which the parent halogen anions remain at equatorial positions preventing the formation of geometries compatible with those found for X=TfO- and SbF6-.
Publisher: Wiley
Date: 09-02-2023
Abstract: Copper‐catalyzed cross‐coupling reactions of α‐bromoaryl N H‐sulfoximines with elemental sulfur lead to benzo[ d ][1,3,2]dithiazole‐1‐oxides, which represent a new class of three‐dimensional heterocycles. The reactions proceed under mild conditions showing good functional group and heterocycle tolerance. By imination/oxidation, the initial cross‐coupling products can be converted to unprecedented cyclic sulfonimidamides derivatives. Furthermore, a seven‐membered heterocycle was obtained by a ruthenium‐catalyzed ring‐expansion with ethyl propiolate. magnified image
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3RA41527A
Publisher: American Chemical Society (ACS)
Date: 29-04-2003
DOI: 10.1021/JA027870W
Abstract: The structure of Cu(II) complex 3 formed within the course of a stereoselective Diels-Alder reaction was investigated by EXAFS, CW-EPR at X- and W-band, HYSCORE, pulsed ENDOR, and UV-vis spectroscopy. The experimental techniques indicate that the chiral bis(sulfoximine) ligand (S,S)-1 and the dienophile form a tetragonally distorted complex in CH(2)Cl(2). The ligand binds to the Cu(II) center via the imine nitrogens, whereas the dienophile interacts via the carbonyl oxygen atoms. The additional sites of the first coordination sphere are occupied by counterions and, presumably, solvent molecules. At the axial position, a triflate anion binds via an oxygen atom.
Publisher: Wiley
Date: 10-02-2013
Abstract: CH(3)CN and O(2) do the trick! A copper-mediated direct oxidative cross-coupling of 2-(het)aryl-1,3,4-oxadiazoles with polyhaloarenes under mild reaction conditions has been developed (see scheme). The process provides a concise access to biaryl structures containing polyhaloarenes, which are of interest in the fields of pharmaceuticals and functional materials. Acetonitrile and oxygen play crucial roles.
Publisher: American Chemical Society (ACS)
Date: 30-04-2014
DOI: 10.1021/OL500963P
Abstract: A high-yielding method providing rapid access to new N-arylated sulfoximines has been developed. A stoichiometric amount of copper facilitates the C-H activation of 2-arylpyridines which then undergo oxidative C-N cross-couplings with various sulfoximine derivatives.
Publisher: American Chemical Society (ACS)
Date: 24-12-2013
DOI: 10.1021/JO402457X
Abstract: Light-induced Brook rearrangements of acylsilanes facilitate silylacylation reactions of electron-deficient internal alkynes. A wide range of aromatic substituents on the acylsilane aryl group are tolerated, affording a series of functionalized enonyl silanes. The presence of electron-withdrawing substituents on the alkyne is crucial for the success of the addition process.
Publisher: Wiley
Date: 10-04-2015
Publisher: Wiley
Date: 13-05-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3GC00442B
Abstract: By using a very low catalyst loading, a wide range of cyclic sulfoximine derivatives, that represent common cores of bioactive products, can be prepared in good to excellent yields at room temperature in a short period of time.
Publisher: Wiley
Date: 10-2006
Publisher: Wiley
Date: 28-08-2013
Publisher: Wiley
Date: 12-06-2023
Abstract: Sulfondiimines are marginalized entities among nitrogen‐containing organosulfur compounds, despite offering promising properties for applications in various fields including medicinal and agrochemical. Herein, we present a metal‐free and rapid synthetic procedure for the synthesis of N ‐monosubstituted sulfondiimines that overcomes current limitations in their synthetic accessibility. Particularly, S , S ‐dialkyl substrates, which are commonly difficult to convert by existing methods, react well with a combination of iodine, 1,8‐diazabicyclo[5.4.0]undec‐7‐en (DBU), and iminoiodinanes (PhINR) in acetonitrile (MeCN) to furnish the corresponding sulfondiimines in yields up to 85 % (25 ex les). Valuable “free” N H‐ N ′H‐sulfondiimines can then be accessed by N ‐deprotection under mild reaction conditions. Several experimental observations suggest a mechanistic pathway erging from the common radical‐based iodine/iminoiodinane mechanism. Based on the experimental results in combination with data obtained by 1 H NMR spectroscopy, ESI mass spectrometry, and crystallographic analysis we propose a direct amination from PhINNs and a reaction path via a cationic iodonitrene.
Publisher: American Chemical Society (ACS)
Date: 26-11-2013
DOI: 10.1021/OL403106E
Abstract: A method has been developed for the preparation of N-alkynylated sulfoximines involving the copper-catalyzed decarboxylative coupling of sulfoximines with aryl propiolic acids. A range of substituents on both the sulfoximidoyl moiety and the aryl group of the propiolic acid were compatible with this reaction process to afford a series of sulfoximidoyl-functionalized alkynes.
Publisher: Wiley
Date: 30-07-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CS60154D
Abstract: The Willgerodt-Kindler reaction has, in recent years, received limited attention and application in synthetic organic chemistry. With the advent of new technology such as microwave-assisted heating, several new, high-yielding, practical, and more environmentally friendly reaction protocols have been developed. This review aims to once again draw attention to this relatively underutilised process by highlighting the recent developments in the Willgerodt-Kindler reaction in the synthesis of (thio)amides, carboxylic acids, and heterocycles.
Publisher: Wiley
Date: 19-11-2013
Abstract: Acylsilanes are known to undergo a 1,2-silicon-to-oxygen migration under thermal or photochemical conditions to form siloxycarbenes. However, there are few reports regarding the application of siloxycarbenes in organic synthesis and surprisingly, their reaction with CC double or triple bonds remains virtually unexplored. To facilitate such a study, previously inaccessible aromatic acylsilanes containing an ortho-tethered CC double bond were identified as suitable substrates. To access these key intermediates, we developed a new synthetic method utilizing a rhodium-catalyzed oxidative Heck-type olefination involving the application of an acylsilane moiety as a directing group. When exposed to visible-light irradiation, the ortho-olefinated acylsilanes underwent a smooth intramolecular cyclization process to afford valuable indanone derivatives in quantitative yields. This result paves the way for the development of new transformations involving siloxycarbene intermediates.
Publisher: American Chemical Society (ACS)
Date: 03-03-2014
DOI: 10.1021/OL5003016
Abstract: An investigation into the reactivity profile of N-halogenated sulfoximines has led to the development of a new method for the synthesis of N-aroylated sulfoximines. This protocol involves the manganese oxide promoted C-H activation of methyl arenes to form an aroyl intermediate which then reacts readily with N-chlorosulfoximines to form a series of valuable aroyl sulfoximine derivatives in high yields.
Publisher: American Chemical Society (ACS)
Date: 23-10-2013
DOI: 10.1021/OL4026028
Abstract: To assess the potential of N-alkynylated sulfoximines as new (chiral) reagents for organic synthesis, their reactivity profile in numerous synthetic processes is under investigation. When reacted with ketenes, the alkynylated-sulfoximines undergo a [2 + 2]-cycloaddition process to afford sulfoximine-functionalized cyclobutenones in excellent yields.
Publisher: Beilstein Institut
Date: 23-11-2022
Abstract: Cholesterol reacts under Appel conditions (CBr 4 /PPh 3 ) to give 3,5-cholestadiene (elimination) and 3 b -bromocholest-5-ene (substitution with retention of configuration). Thus, the bromination of cholesterol deviates from the stereochemistry of the standard Appel mechanism due to participation of the D 5 π -electrons. In contrast, the subsequent azidolysis (NaN 3 /DMF) of 3 b -bromocholest-5-ene proceeds predominantly by Walden inversion (S N 2) affording 3 a -azidocholest-5-ene. The structures of all relevant products were revealed by X-ray single crystal structure analyses, and the NMR data are in agreement to the reported ones. In light of these findings, we herein correct the previous stereochemical assignments reported by one of us in the Beilstein J. Org. Chem. 2015 , 11 , 1922–1932 and the Monatsh. Chem. 2018 , 149 , 505–517.
Publisher: Beilstein Institut
Date: 27-01-2023
DOI: 10.3762/BJOC.19.9
Abstract: Cholesterol reacts under Appel conditions (CBr 4 /PPh 3 ) to give 3,5-cholestadiene (elimination) and 3β-bromocholest-5-ene (substitution with retention of configuration). Thus, the bromination of cholesterol deviates from the stereochemistry of the standard Appel mechanism due to participation of the Δ 5 π-electrons. In contrast, the subsequent azidolysis (NaN 3 /DMF) of 3β-bromocholest-5-ene proceeds predominantly by Walden inversion (S N 2) affording 3α-azidocholest-5-ene. The structures of all relevant products were revealed by X-ray single crystal structure analyses, and the NMR data are in agreement to the reported ones. In light of these findings, we herein correct the previous stereochemical assignments reported by one of us in the Beilstein J. Org. Chem. 2015 , 11 , 1922–1932 and the Monatsh. Chem. 2018 , 149 , 505–517.
Location: United States of America
Location: Germany
No related grants have been discovered for Carsten Bolm.