Rh(I)-Bisphosphine-Catalyzed Asymmetric, Intermolecular Hydroheteroarylation of α-Substituted Acrylate Derivatives was written by Filloux, Claire M.;Rovis, Tomislav. And the article was included in Journal of the American Chemical Society in 2015.SDS of cas: 132227-03-3 This article mentions the following:
Asym. hydroheteroarylation of alkenes represents a convenient entry to elaborated heterocyclic motifs. While chiral acids are known to mediate asym. addition of electron-rich heteroarenes to Michael acceptors, very few methods exploit transition metals to catalyze alkylation of heterocycles with olefins via a C-H activation, migratory insertion sequence. Herein, we describe the development of an asym., intermol. hydroheteroarylation reaction of α-substituted acrylates with benzoxazoles. The reaction provides 2-substituted benzoxazoles in moderate to excellent yields and good to excellent enantioselectivities [e.g., 4-methylbenzoxazole + Et methacrylate → I (88% yield, 94% ee)]. Notably, a series of mechanistic studies appears to contradict a pathway involving enantioselective protonation of a Rh(I)-enolate, despite the fact that such a mechanism is invoked almost unanimously in the related addition of aryl boronic acids to methacrylate derivatives Evidence suggests instead that migratory insertion or beta-hydride elimination is enantiodetermining and that isomerization of a Rh(I)-enolate to a Rh(I)-heterobenzyl species insulates the resultant α-stereocenter from epimerization. A bulky ligand, CTH-(R)-Xylyl-P-Phos, is crucial for reactivity and enantioselectivity, as it likely discourages undesired ligation of benzoxazole substrates or intermediates to on- or off-cycle rhodium complexes and attenuates coordination-promoted product epimerization. In the experiment, the researchers used many compounds, for example, 5-Methoxybenzo[d]oxazole (cas: 132227-03-3SDS of cas: 132227-03-3).
5-Methoxybenzo[d]oxazole (cas: 132227-03-3) belongs to benzoxazole derivatives. Benzoxazole nucleus is one of the most important heterocyclic compounds exhibiting remarkable pharmacological activities. In the past years, numerous benzoxazole derivatives have been synthesised and evaluated for their biological potential.SDS of cas: 132227-03-3
Referemce:
Benzoxazole – Wikipedia,
Benzoxazole | C7H5NO – PubChem