14316-14-4Relevant academic research and scientific papers
Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s
Hoogenboom, Richard,Fijten, Martin W. M.,Kickelbick, Guido,Schubert, Ulrich S.
, p. 773 - 783 (2010)
The synthesis of well-defined polymer architectures is of major importance for the development of complex functional materials. In this contribution, we discuss the synthesis of a range of multifunctional star-shaped tosylates as potential initiators for the living cationic ring-opening polymerization (CROP) of 2-oxazolines resulting in star-shaped polymers. The synthesis of the tosylates was performed by esterification of the corresponding alcohols with tosyl chloride. Recrystallization of these tosylate compounds afforded single crystals, and the X-ray crystal structures of di-, tetra-and hexa-tosylates are reported. The use of tetra-and hexatosylates, based on (di)pentaerythritol as initiators for the CROP of 2-ethyl-2-oxazoline, resulted in very slow initiation and illdefined polymers, which is most likely caused by steric hindrance in these initiators. As a consequence, a porphyrin-cored tetratosylate initiator was prepared, which yielded a well-defined star-shaped poly(2-ethyl-2-oxazoline) by CROP as demonstrated by SEC with RI, UV and diode-array detectors, as well as by 1H NMR spectroscopy.
Catalyst-Free Visible-Light-Mediated Iodoamination of Olefins and Synthetic Applications
Engl, Sebastian,Reiser, Oliver
supporting information, p. 5581 - 5586 (2021/07/26)
Herein we report a catalyst- and metal-free visible-light-mediated protocol enabling the iodoamination of miscellaneous olefins. This protocol is characterized by high yields under environmentally benign reaction conditions utilizing commercially available substrates and a green and biodegradable solvent. Furthermore, the protocol allows for late-stage functionalization of bioactive molecules and can be scaled to gram quantities of product, which offers manifold possibilities for further transformations, including morpholine, piperidine, pyrrolidine, and aziridine synthesis.
Dual Nickel- And Photoredox-Catalyzed Reductive Cross-Coupling to Access Chiral Trifluoromethylated Alkanes
Zhou, Pan,Li, Xinxuan,Wang, Dong,Xu, Tao
supporting information, p. 4683 - 4687 (2021/06/28)
A dual nickel/photoredox-catalyzed enantioselective reductive cross-coupling of aryl halides with CF3-substituted racemic alkyl electrophiles has been established. The approach accommodates a broad palette of aryl iodides and alkyl bromides to access a va
Enantio- and Regioselective Palladium(II)-Catalyzed Dioxygenation of (Aza-)Alkenols
Beccalli, Egle Maria,Giofrè, Sabrina,Lo Presti, Leonardo,Molteni, Letizia,Nava, Donatella
supporting information, p. 21723 - 21727 (2021/09/08)
An oxidative Pd-catalyzed intra-intermolecular dioxygenation of (aza-)alkenols has been reported, with total regioselectivity. To study the stereoselectivity, different chiral ligands as well as different hypervalent-iodine compounds have been compared. I
Copper-catalyzed enantioselective alkene carboetherification for the synthesis of saturated six-membered cyclic ethers
Berhane, Ilyas A.,Burde, Ameya S.,Chemler, Sherry R.,Kennedy-Ellis, Jonathan J.,Zurek, Eva
supporting information, p. 10099 - 10102 (2021/10/06)
The enantioselective copper-catalyzed oxidative coupling of alkenols with styrenes for the construction of dihydropyrans, isochromans, pyrans and morpholines is reported. A concise formal synthesis of a σ1receptor ligand using this alkene carbo
Electrochemical C?H Amidation of Heteroarenes with N-Alkyl Sulfonamides in Aqueous Medium
Zhang, Yan,Lin, Zhipeng,Ackermann, Lutz
supporting information, p. 242 - 246 (2020/11/30)
The construction of C?N bonds by free radical reactions represents a powerful synthetic approach for direct C?H amidations of arenes or heteroarenes. Developing efficient and more environmentally friendly synthetic methods for C?H amidation reactions remains highly desirable. Herein, metal-free electrochemical oxidative dehydrogenative C?H amidations of heteroarenes with N-alkylsulfonamides have been accomplished. The catalyst- and chemical-oxidant-free C?H amidation features an ample scope and employs electricity as the green and sole oxidant. A variety of heteroarenes, including indoles, pyrroles, benzofuran and benzothiophene, thereby underwent this C(sp2)?H nitrogenation. Cyclic voltammetry studies and control experiments provided evidence for nitrogen-centered radicals being directly generated under metal-free electrocatalysis.
Synthesis of Quinolinium Salts from N-Substituted Anilines, Aldehydes, Alkynes, and Acids: Theoretical Understanding of the Mechanism and Regioselectivity
Chao, Tzu-Hsuan,Chen, Wei-Chen,Cheng, Chien-Hong,Cheng, Lin-Chieh,Cheng, Mu-Jeng,Santhoshkumar, Rajagopal
supporting information, p. 2116 - 2129 (2020/04/23)
Secondary anilines were first utilized in the four-component coupling of aniline, aldehyde, alkyne, and acid to synthesize a variety of N-substituted quinolinium salts. This method was carried out under mild reaction conditions and exhibited excellent chemo- and regioselectivities. DFT calculation was performed to analyze the cyclization step, where the interaction/distortion model provided better insight into the singular selectivity of terminal/internal alkynes in reaction.
Sustainable Palladium-Catalyzed Tsuji-Trost Reactions Enabled by Aqueous Micellar Catalysis
Braga, Felipe C.,Gallou, Fabrice,Lee, Nicholas R.,Lippincott, Daniel J.,Lipshutz, Bruce H.,Moghadam, Farbod A.,Zhu, Bingchun
supporting information, (2020/07/15)
Palladium-catalyzed allylic substitution, or "Tsuji-Trost"reactions, can be run under micellar catalysis conditions featuring not only chemistry in water but also numerous combinations of reaction partners that require low levels of palladium, typically on the order of 1000 ppm (0.1 mol %). These couplings are further characterized by especially mild conditions, leading to a number of cases not previously reported in an aqueous micellar medium. Inclusion of diverse nucleophiles, such as N-H heterocycles, alcohols, dicarbonyl compounds, and sulfonamides is described. Intramolecular cyclizations further illustrate the broad utility of this process. In addition to recycling studies, a multigram scale example is reported, indicative of the prospects for scale up.
α-Functionalisation of Ketones Through Metal-Free Electrophilic Activation
González, Leticia,Maryasin, Boris,Maulide, Nuno,Mishevska, Magdalena,Teskey, Christopher J.,V?lkl, Martin,Zawodny, Wojciech
supporting information, p. 20935 - 20939 (2020/10/02)
Triflic anhydride mediated activation of acetophenones leads to highly electrophilic intermediates that can undergo a variety of transformations when treated with nucleophiles. This electrophilic ketone activation gives access to α-arylated and α-oxyamina
Ni-Catalyzed Cyclization of Enynes and Alkynylboronates: Atom-Economical Synthesis of Boryl-1,4-dienes
Cabrera-Lobera, Natalia,Quirós, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
supporting information, p. 14512 - 14516 (2019/11/11)
We report a novel atom-economical Ni-catalyzed cyclization reaction of enynes with alkynylboronates. The reaction employs a non-expensive Ni salt, a phosphine-based ligand and easy-handling alkynylboronates as boron–carbon source. The reaction provides co
