Efficient Cleavage–Cross-Coupling Strategy for Solid-Phase Synthesis—A Modular Building System for Combinatorial Chemistry

Abstract

A new modular building system for the combinatorial chemistry was developed on the basis of triazene linkers. Starting from an aniline system, further functional units and virtually any alkene or alkyne as terminator furnished lipophilic multicomponent systems in high yields and purities without the need for purification steps (see schematic representation).

Palladium-catalyzed cross-coupling reactions and electrocyclizations—efficient combinations for new cascade reactions

“…More recently, this reaction has been widely explored and shown to have reasonably high combinatorial potential since not only can different aryl halides and different dienophiles, but even differently substituted bicyclopropylidenes, be employed [8]. Furthermore, multiple couplings with oligoiodoarenes [8b, d,9] have been performed as well as couplings with aryl iodides bound to a solid phase, employing the triazene linker methodology of Bräse and coworkers [10] (Scheme 2).…”

Cross‐Coupling of Organyl Halides with Alkenes – The Heck Reaction

“…In some cases, Pd 2 (dba) 3 ·CHCl 3 was found to be far more effective than Pd(OAc) 2 [579]. The Heck reaction was performed on immobilized aryl halides, mostly iodides, or aryliodonium salts with soluble alkenes [122,209,210,[580][581][582][583][584][585][586][587][588][589][590] or on immobilized alkenes with soluble aryl halides [110e, 217a, [601][602][603][604][605][606] as well as with soluble aryliodonium salts [217b]. When performed on the same type of resin and with the same catalyst system, the immobilization of the aryl iodide appears to be more beneficial than that of the alkene [210].…”

“…This new threecomponent reaction has also been conducted on a solid support using the versatile triazene T1 linker (Scheme 8.90) [122,604]. The Heck coupling of an immobilized iodoarene 468 with bicyclopropylidene (16) in the presence of an acrylate forms a polymer-bound 4-arylspirooctenecarboxylate 469.…”

“…The triazene moieties upon cleavage with acid first yield diazonium salts, which in turn can be involved in the Heck reactions with various alkenes to give the additionally substituted spirooctenes 471 and 473 in good yields and excellent purities. When palladium on charcoal is employed for this transformation, the same catalyst may also serve for a subsequent catalytic hydrogenation of the double bond in the alkene-coupled product [122,604].…”

Lectin-vermitteltes Drug-Targeting: Diskriminierung zwischen der Kohlenhydrat-vermittelten Aufnahme von Neoglycokonjugaten, die in 3-Position modifizierte Fucose-Epitope tragen, in Tumor- oder Leberzellen

“…[12] Die cis-Hydroxygruppe von 2 wird mit Dibutylzinnoxid in Methanol in das Zinnacetal 3 überführt. Nach Entfernen des Methanols und Zusatz von Alkylierungsmitteln wie Methyliodid oder Bromessigsäuremethylester in DMF oder Dioxan wird das Zinnacetal unter Alkylierung der reaktiveren äquatorialen Position mit hoher Regioselektivität geöffnet.…”