A group effort: Reported is the title reaction using a polycomponent catalytic system involving commercially available Selectfluor, putative radical precursor N-hydroxyphthalimide, an anionic phase-transfer catalyst (KB(C6F5)4), and copper(I) bis(imine). The formed leads to monofluorinated compounds selectively (see example) without necessity for excess of alkane substrate. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed,...

Recently, our group unveiled a system in which an unusual interplay between copper(I) and Selectfluor effects mild, catalytic sp(3) C-H fluorination. Herein, we report detailed reaction mechanism based on exhaustive EPR, (19)F NMR, UV-vis, electrochemical, kinetic, synthetic, computational studies that, to surprise, was revealed be radical chain copper acts as initiator. Furthermore, offer explanation for the notable but curious preference monofluorination by ascribing ionic character...

Direct C–F functionalization of benzylic sp3 C–H bonds is a synthetic challenge that has yet to be propitiously overcome. A mild, one-pot synthesis monofluorinated substrates reported with commercially available iron(II) acetylacetonate and Selectfluor in good excellent yields selectivity. convenient route β-fluorinated products 3-aryl ketones also highlighted, providing equivalent the difficult accomplish conjugate addition fluoride α,β-unsaturated ketones.

We disclose a new approach to the catalysis of alkane fluorination employing ultraviolet light and photosensitizer, 1,2,4,5-tetracyanobenzene (TCB).

The photocatalyzed oxidation of benzylic compounds by 1,2,4,5-tetracyanobenzene (TCB) in the presence Selectfluor provides a synthetically efficient route to electron deficient, less substituted, and otherwise inaccessible fluorides. virtue this system is multifold: it metal-free mild, reagents are inexpensive. Mechanistically, data suggest intimate formation intermediate radical cations key forming step, as opposed concerted hydrogen atom transfer process.

Abstract To expand upon the recent pioneering reports of catalyzed sp 3 CH fluorination methods, next rational step is to focus on directing “radical‐based fluorination” more effectively. One potential solution entails selective CC bond activation as a prelude fluorination. Herein, we report tandem photocatalyzed ring‐opening/fluorination reactions cyclopropanols by 1,2,4,5‐tetracyanobenzene (TCB) and Selectfluor afford process tantamount site‐selective β‐fluorination carbonyl‐containing...

Carbon-centered radicals are indispensable building blocks for modern synthetic chemistry. In recent years, visible light photoredox catalysis has become a promising avenue to access C-centered from broad array of latent functional groups, including boronic acids. Herein, we present an aqueous protocol wherein water features starring role help transform aliphatic, aromatic, and heteroaromatic acids with bioinspired flavin photocatalyst. These used deliver diverse pool alkylated products,...

Most peptide drugs contain non-proteinogenic amino acids (NPAAs), born out through extensive structure-activity relationship (SAR) studies using solid-phase synthesis (SPPS). Synthetically laborious and expensive to manufacture, NPAAs also can have poor coupling efficiencies allowing only a small fraction be sampled by conventional SPPS. To gain general access NPAA-containing peptides, we developed first-generation platform that merges contemporary flavin photocatalysis with parallel...

Große Kooperation: Die Titelreaktion mit einem Mehrkomponenten-Katalysesystem aus dem käuflichen Selectfluor, der Radikalquelle N-Hydroxyphthalimid, anionischen Phasentransferkatalysator KB(C6F5)4 und Kupfer(I)-Diimin-Komplex liefert selektiv die monofluorierten Produkte (siehe Beispiel), ohne dass ein Überschuss des Alkansubstrats eingesetzt werden müsste. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not...

We explore in detail the iron-catalyzed benzylic fluorination of substrates containing aromatic rings and electron-withdrawing groups positioned β to one another, thus providing direct access β-fluorinated adducts. This operationally convenient process can be thought not only as a contribution timely problem but also functional equivalent conjugate addition fluoride, furnishing products moderate good yields excellent selectivity.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVinyllithium cyclizations with unactivated alkenes as internal electrophiles: stereoselective formation of substituted methylenecyclopentanesA. Richard. Chamberlin, Steven H. Bloom, Laura A. Cervini, and Christopher FotschCite this: J. Am. Chem. Soc. 1988, 110, 14, 4788–4796Publication Date (Print):July 1, 1988Publication History Published online1 May 2002Published inissue 1 July...

The selective α,α-difluorination of carbonyl compounds remains a challenge in modern organic synthesis; current methods often incorporate stepwise processes and/or harsh conditions, providing unsatisfactory mixtures mono- and difluorinated products. In this communication, practical, mild, one-pot method for the readily available acid chlorides is reported which three separate catalysts act synergistically to form products outstanding selectivity fair excellent yields.

We analyze the structures and spectral signatures of cyclic intramolecular proton bond, N-H(+)-A, A = O F, formed when an excess is added to derivatives 1,8-disubstituted naphthalene scaffold. These compounds provide a quasi-rigid framework with which study complexity often associated N-H(+)-A entity. Vibrational spectra were obtained by monitoring photodissociation weakly bound H2 adducts mass-selected ions cooled close 10 K. Several bands across 900-3500 cm(-1) range traced involvement...

Combining a transition metal with photocatalyst can drive modern synthetic chemistry. For transformations performed in water, this concept has been largely unexplored. We report the successful merger of biocompatible flavin palladium catalyst to build isotopically enriched peptidomimetics, mediate conjugate addition and C-H functionalization reactions, assemble unprotected proteinogenic nonproteinogenic peptides, water. detail important role ligand oxidation state for controlling product...

One way to improve the therapeutic potential of peptides is through cyclization. This commonly done using a disulfide bond between two cysteine residues in peptide. However, bonds are susceptible reductive cleavage, and this can deactivate peptide endanger endogenous proteins covalent modification. Substituting with more chemically robust carbon-based linkers has proven be an effective strategy better develop cyclic as drugs, but finding optimal carbon replacement synthetically laborious. We...

We describe the synthesis and preliminary study of two molecules, in which a fluorine atom is positioned proximately above π-orbitals C═C bond or else wherein C-F interacts "head on" fashion with proximate C-H bond. The spectroscopic characteristics these unusual interactions are documented, X-ray crystallographic analyses reported, theoretical calculations employed to support observed spectroscopy.

We characterize a highly unusual, charged NH-O hydrogen bond formed within esters of 8-(dimethylamino)naphthalen-1-ol in which an ammonium ion serves as intramolecular donor to spatially proximate ester ether oxygen atoms. Infrared spectroscopic analysis the carbonyl frequencies demonstrates significant blue-shifting when bonding is possible, stark contrast more commonly observed red shift that occurs upon oxygen. The intrinsic behavior linkage (i.e., counterions and solvent effects are...

Methods for the selective labeling of biogenic functional groups on peptides are being developed and used in workflow both current emerging proteomics technologies, such as single-molecule fluorosequencing. To achieve successful with any one method requires that peptide fragments contain group which chemistry is designed. In practice, only two present every fragment regardless protein cleavage site, namely, an N-terminal amine a C-terminal carboxylic acid. Developing global-labeling...

Exchanging the ribose backbone of an oligonucleotide for a peptide can enhance its physiologic stability and nucleic acid binding affinity. Ordinarily, eneamino nitrogen atom nucleobase is fused to side chain polypeptide through new C-N bond. The discovery C-C linked nucleobases in human transcriptome reveals opportunities engineering nucleopeptides that replace traditional bond with non-classical bond, liberating captive promoting hydrogen bonding π-stacking interactions. We report first...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIodolactamization of .gamma.,.delta.-unsaturated oxazolinesMark J. Kurth and Steven H. BloomCite this: Org. Chem. 1989, 54, 2, 411–414Publication Date (Print):January 1, 1989Publication History Published online1 May 2002Published inissue 1 January 1989https://doi.org/10.1021/jo00263a028RIGHTS & PERMISSIONSArticle Views207Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text article downloads since...

One untapped reactivity mode of flavins is excited-state proton transfer. We show that electrophotochemistry enables to achieve this elusive reactivity, in addition C–H functionalization protocols, expanding their mechanistic repertoire.

One way to build chemical diversity into indoles is oxidize them indolyl radical cations (Ind•+). These intermediates can accept new functional groups across C2–C3 bonds or independently at C2. Less encountered selective diversification C3, a position plagued by competing dearomative side reactions. We disclose an aqueous photoredox-catalyzed method for transforming Ind•+ C3-substituted tryptophan mimetics that uses water as transient protecting group guide site-selective C3 alkylation.