β-Hydroxy and β-(o-diphosphino)benzoyloxy(o-diphosphino) benzamides as ligands for asymmetric allylic alkylation

Evaluation of phosphinoamidoester‐derived Pd catalysts in the asymmetric allylic alkylation reaction: Theoretical studies and mechanistic insights

“…A highest enantioselectivity of 83% was obtained. (Table 1—entry 1) almost equalling the value obtained by Mino8 and superseding the value obtained by Hitchcock and coworkers 11. In all cases, when rac ‐1,3‐diphenylpropenyl acetate was used, the major isomer has the ( S ) absolute configuration, the same as that obtained with the phosphinoamide‐alcohol ligand 6b 10 and which suggests a similar mechanism (unfortunately, we were unable to access and test in this reaction the phosphinoamideOL analog derived from ( S )‐valinol and 7 ).…”

“…Hitchcock and coworkers11 demonstrated that the (1 S, 2 S )‐pseudonorephedrine derived complex 10 (obtained from 5 , Fig. 1, R 1 = H, R 2 = Ph) afforded the ( R )‐malonate product as the major enantiomer.…”

“…We recently introduced the analogs of Mino's phosphinoamide ligands 4a and 4b 10 (phosphinoamideOLs), which were reasonably successful for this reaction (a highest ee of 62% was achieved) 10. Shortly afterward, Hitchcock and coworkers11 reported the synthesis and application of the norephedrine and pseudonorephedrine analogs 5 in this reaction (Fig. 1) that furnished slightly greater enantioselectivities (up to 75% ee ).…”

A Novel 1‐Glycosyl‐1H‐triazole‐Based P,N Ligand for Rhodium‐Catalyzed Asymmetric Hydrosilylation of Ketones

“…-Over the last few decades, the asymmetric Rh-catalyzed hydrosilylation of ketones has been recognized as a versatile method for the synthesis of enantiomerically enriched alcohols and amines [1]. The chiral catalysts for asymmetric hydrosilylation were based on neutral cationic Rh precursors in combination with chiral bidentate diphosphines and amines to mixed donor-atom moieties [2], such as phosphino ethers [3], phosphino thioethers [4], and aminophosphines [5]. These catalytic systems have been applied to asymmetric hydroformylation, hydrogenation, hydrosilylation, and allylic alkylation reactions.…”

“…Numerous configurations of phosphorus,nitrogen (P,N) ligands have been reported [6]. The P,N ligands can be generically divided into two categories, namely those based on structurally rigid sp 2 -Ncenters, unsaturated pyridine or imine groups [7], and the other are sp 3 -N-centers, which constitute saturated amine functionalities [8]. Click chemistry has recently attracted considerable attention as a powerful and efficient way to synthesize desired compounds in high yields by using a simple and benign procedure [9].…”