Stereoselective Direct Copper-Catalyzed Alkenylation of Oxazoles with Bromoalkenes

Abstract

A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.

Transition‐Metal‐Catalyzed Direct Arylation of (Hetero)Arenes by CH Bond Cleavage

“…[193] Highly regio-and diastereoselective copper-catalyzed direct alkenylations of oxazoles were realized with vicinal diamine 272 as the ligand. [194] As was previously observed, the addition of the strong base LiOtBu was mandatory. The scope of this procedure was highlighted by the efficient synthesis of alkaloid annuloline ((E)-271; Scheme 101).…”

Übergangsmetallkatalysierte direkte Arylierungen von (Hetero)Arenen durch C‐H‐Bindungsbruch

“…[193] Durch Verwendung des vicinalen Diamins 272 konnten hoch regio-und diastereoselektive kupferkatalysierte direkte Alkenylierungen von Oxazolen realisiert werden. [194] Auch hier war die Zugabe der starken Base LiOtBu obligatorisch. Die Anwendungsbreite dieses Verfahrens wurde anhand einer effizienten Synthese des Alkaloids Annulolin (E-271) demonstriert (Schema 101).…”

Pd/Cu‐Catalyzed Direct Alkenylation of Azole Heterocycles with Alkenyl Halides

“…In these instances, a very few number of heterocycles were studied. Grierson et al [2] reported direct alkenylation of 5-phenyloxazoles with (E)-β-bromostyrenes under copper catalysis. Other groups have extended this methodology to the palladiumcatalyzed alkenylation of other oxazoles, including 5-aryloxazoles [3] and ethyl oxazole-4-carboxylate.…”