Katalytische Umwandlung von funktionalisierten cyclischen organischen Carbonaten

Abstract

Funktionalisierte cyclische organische Carbonate und deren heterocyclischen Derivate sind eine sehr vielseitige Gruppe heterocyclischer Substrate, deren katalytische Ringöffnung und Decarboxylierung die Entwicklung neuartiger Synthesewege zur Herstellung stereo‐ und enantioselektiver C‐N‐, C‐O‐, C‐C‐, C‐S‐ und C‐B‐Bindungen ermöglicht. Erst kürzlich wurden Übergangsmetall‐vermittelte Umwandlungen als wirksame Methode zur Synthese komplexerer Moleküle wiederentdeckt. Dieser Kurzaufsatz illustriert das Potential cyclischer Carbonate und ihrer strukturell verwandten Heterocyclen, mit einem besonderen Fokus auf dem synthetischen Nutzen und der mechanistischen Mannigfaltigkeit ihrer Umwandlungen.

A Mechanistic Analysis of the Palladium‐Catalyzed Formation of Branched Allylic Amines Reveals the Origin of the Regio‐ and Enantioselectivity through a Unique Inner‐Sphere Pathway

“…[6] Recently,P d-catalyzed efficient decarboxylative transformations of vinylethylene carbonates (VCCs) with various electrophiles and (pro)nucleophiles have been reported. [7][8][9][10] In this context, Kleij, Maseras and co-workers developed aP d-catalyzed allylic substitution of VCCs 1 with aryl-and alkyl-amines (Scheme 1c). [8] Notably,w ith the diphosphine ligand L1,c omplete linear regioselectivity and high (Z)stereoselectivity was observed, thus providing ag eneral method for the stereoselective construction of tri-and tetrasubstituted allylic amines (Z)-2.Adetailed reaction mechanism was also provided by DFT calculations,a nd the computational results showed that the reaction follows ag enerally accepted outer-sphere pathway in line with the experimental results.A talater stage,K leij and co-workers found that the regioselectivity of this reaction can be switched towards the branched product through ligand control.…”

Pd‐Catalyzed Umpolung of η3‐Benzylpalladium Enabled the Construction of All‐Carbon α‐Vinyl Quaternary Aldehydes

“…The presence of a vinyl group is proved to be crucial to promote the reaction [11,12] . Driven by our continuous interests on the development of decarboxylative chemistry, [10a–d] we envisaged that if the benzylpalladium intermediate t1 could be generated though decarboxylation of an aryl cyclic carbonate 1 (Scheme 1c); an umpolung process via a β ‐hydride elimination step would result in intermediate t2 featuring an enolate fragment; the nucleophilic t2 can be captured easily by cationic π ‐allylic‐Pd, thus correspondingly developing the first case of dearomative umpolung strategy. Herein, we report our latest results on this project.…”

Pd‐Catalyzed Stereodivergent Allylic Amination of α‐Tertiary Allylic Alcohols towards α,β‐Unsaturated γ‐Amino Acids

“…[8] Althoughe fficient methodologies have been developed for the construction of the thermodynamically (typically) more stable (E)-configured, g-mono-substituted allylic amine scaffolds( Scheme 1a), [9] reports pertaining to stereodivergent allylic amination affording either a( Z)-or (E)-configured product from as ingle substrate are scarce. [10] The key to the success of this approach was the in situ formation of as ix-membered palladacyclici ntermediate (computed by DFT;S cheme 1b). [10] The key to the success of this approach was the in situ formation of as ix-membered palladacyclici ntermediate (computed by DFT;S cheme 1b).…”