Asymmetric Allylic Oxidation with Biarylbisoxazoline-Copper(I) Catalysis

Rigid backbone 1,8-anthracene-linked bis-oxazolines (AnBOXes): design, synthesis, application and characteristics in catalytic asymmetric aziridination

“…The diamides 3 were activated with SOCl 2 in THF to yield dichlorodiamides, which were treated with K 2 CO 3 in a mixture of CH 3 CN-H 2 O as a co-solvent to produce 1,8-bisoxazolinylanthracenes 2 (AnBOXes) in satisfactory yields. 22 In most cases, the intermediates 3 were used without further purification due to their poor solubility. The final ligands were conveniently purified by silica gel chromatography (Scheme 2).…”

Catalytic Allylic Oxidation of Alkenes Using an Asymmetric Kharasch–Sosnovsky Reaction

“…Andrus and co-workers have further probed the effect of additional stereogenicity in the bis(oxazoline) backbone by employing the diastereoisomeric biaryl atropisomeric oxazolines 20, (Scheme 8). [9,10] The wider bite angle between the two nitrogen atoms and the copper center was expected to improve selectivity for both ligands, by forcing the reacting allyl and benzoate groups closer together in 4. However, it was found that the (S,S,S)-oxazoline 20 a gave much better stereocontrol than the related (S,R,S) stereoisomer 20 b (76 % yield, 0 % ee).…”

Heterogenization of chiral mono oxazoline ligands by grafting onto mesoporous silica MCM-41 and their application in copper-catalyzed asymmetric allylic oxidation of cyclic olefins

“…This reaction has been the subject of great interest over the past decade and provides access to chiral allylic alcohols, which are key intermediates in natural product synthesis [23][24][25][26][27][28][29]. In this paper, we report the preparation and characterization of the chiral heterogeneous catalyst OX-R-MCM-41 as a novel chiral oxazoline-based solid catalyst and employ copper complexes of OX-R-MCM-41 in the enantioselective Kharash-Sosnovsky reaction.…”