Dehydrierende Kreuzkupplungen von C‐H‐Bindungen: vielseitige Verfahren zur Bildung von C‐C‐Bindungen

Abstract

In den vergangenen zehn Jahren wurde eine beeindruckende Zahl an Verfahren entwickelt, die den selektiven Aufbau von C‐C‐Bindungen über die direkte Verknüpfung von zwei unterschiedlichen C‐H‐Bindungen unter oxidativen Bedingungen ermöglichen. Diesen Methoden ist gemeinsam, dass die reaktiven Zwischenstufen durch Aktivierung der beiden C‐H‐Bindungen in situ gebildet werden. Diese Strategie wurde von der Gruppe von Li als dehydrierende Kreuzkupplung (CDC, “cross‐dehydrogenative coupling”) eingeführt und eröffnet abfallarme Synthesealternativen zu klassischen Kupplungsverfahren, die sich auf die Verwendung von vorfunktionalisierten Ausgangsstoffen stützen. Dieser Aufsatz hebt die Fortschritte auf dem Gebiet der dehydrierenden C sp 3‐C‐Bindungsknüpfungen hervor und liefert einen umfassenden Überblick über die vorhandenen Verfahren.

Oxidative C–S bond cleavage reaction of DMSO for C–N and C–C bond formation: new Mannich-type reaction for β-amino ketones

“…1 The most classic method for the preparation of β-amino carbonyl compounds is the threecomponent mannich reaction with aldehydes, amines, and a C−H acidic carbonyl compounds, which has been employed numerous times as a key step in natural product synthesis as well as in 20 medicinal chemistry (eqn 1). 2 In recent years, oxidative mannich reactions, originating from readily available tertiary amines, 3 emerges as a powerful method for preparation β-amino carbonyl compounds with the aid of metal catalyst and oxidant (eqn 2). 4 However, some substrate limitations and side reactions limits its 25 wide application.…”

Iron(III)/Iodine‐Catalyzed C(sp2)H Activation of α,β‐Unsaturated Aldehydes/Ketones with Amidines: Synthesis of 1,2,4,5‐Tetrasubstituted Imidazoles

“…Comparatively,t he substitution on R 4 provided excellentr esults,e ither as ah eteroaromatic ring such as 2-pyridyl as wella se lectron-donating or electronwithdrawing groups (Table 3, entries8-14). Bifunctional and trifunctional amidines were also studied, and were wellc ompatible in this transformation in 84-97% yields ( Table 3, entries [15][16][17][18][19]. Ther eaction tolerated ortho-substitutioni nt he aromatic ring and gave comparable yields to the ones with substitution at the para-position (Table 3, entries 3, 4, 13 and 14).…”

“…[16] Iron is consequently consideredt ob eo ne of the most abundant metals on earth, as well as one of the most inexpensive ande nvironment-friendly ones. [17] At ypiScheme1.Imidazole framework in some pharmaceuticals and ligands.…”

A Copper (II) Acetate Mediated Oxidative‐Coupling of Styrenes and Ethers Through an Unactivated C(sp3)−H Bond Functionalization

“…[1] Especially in recent years, functionalization of unactivated C(sp 3 )ÀH bond has been considered as one of the most effective strategies in organic synthesis. This CÀC bond formation has been developed using t-butyl hydroperoxide (TBHP) as a radical initiator and DBU as an additive agent.…”

“…[1] Especially in recent years, functionalization of unactivated C(sp 3 )ÀH bond has been considered as one of the most effective strategies in organic synthesis. [1] Especially in recent years, functionalization of unactivated C(sp 3 )ÀH bond has been considered as one of the most effective strategies in organic synthesis.…”