Enantioselective Dihydroxylation of Alkenes Catalyzed by 1,4‐Bis(9‐O‐dihydroquinidinyl)phthalazine‐Modified Binaphthyl–Osmium Nanoparticles

Abstract

A series of unprecedented binaphthyl–osmium nanoparticles (OsNPs) with chiral modifiers were applied in the heterogeneous asymmetric dihydroxylation of alkenes. A remarkable size effect of the OsNPs, depending on the density of the covalent organic shells, on the reactivity and enantioselectivity of the dihydroxylation reaction was revealed. Successful recycling of the OsNPs was also demonstrated and high reaction efficiency and enantioselectivity were maintained.

One-Pot Enzymatic–Chemical Cascade Route for Synthesizing Aromatic α-Hydroxy Ketones

“…Additionally, under optimized conditions, the preparative scale transformations for the synthesis of ( S )- and ( R )-PED were achieved. This pathway has three characteristics: (1) it realizes the transformation process of “achiral compounds–prochiral compounds–chiral compounds” to synthesize high-value chemicals through chiral-group resetting; (2) compared with the starting substrates 4-phenyl-1,3-dioxolan-2-one, styrene, and 2-HAP − for synthesis of ( S )- or ( R )-1-phenyl-1,2-ethanediol, it uses the achiral substrates 1a and 2 , which are readily available, inexpensive, and represent sustainable alternatives for producing optically pure 1-phenyl-1,2-ethanediol; and (3) this one-pot enzymatic–chemical cascade reaction can incorporate other enzymes, such as transaminases, to synthesize high-value amino alcohols from 1a and 2 . , …”

Boosting Thermal Stability of Volatile Os Catalysts by Downsizing to Atomically Dispersed Species

“… 8 − 19 Immobilization improved catalyst stability and recyclability; however, Os leaching has still occurred because of the weak interactions between the Os species and the supports. 17 , 19 …”

“…8−19 Immobilization improved catalyst stability and recyclability; however, Os leaching has still occurred because of the weak interactions between the Os species and the supports. 17,19 Recently, with the emergence of atomically dispersed catalysts, new, interesting findings have been uncovered in the field of catalysis. 20−27 Atomically dispersed catalysts have demonstrated unprecedented intrinsic activities or unique selectivities in diverse reactions, 28−34 which have not been displayed by conventional nanoparticle (NP)-based catalysts.…”

“…Furthermore, the high volatility of OsO 4 hinders the reuse of Os catalysts, impeding their commercial development. To mitigate the toxicity and volatility shortcomings, Os-based complexes have been immobilized onto organic or inorganic supports, such as polymers, silica (SiO 2 ), fullerenes, and metal oxides. − Immobilization improved catalyst stability and recyclability; however, Os leaching has still occurred because of the weak interactions between the Os species and the supports. , …”

Cascade Alkynylation and Highly Selective Hydrogenation Catalyzed by Binaphthyl-Palladium Nanoparticles Accessing Phosphinyl (Z)-[3]Dendralenes

“…Metal nanoparticles, a semi-heterogeneous colloid, provide a rationale for enabling such transformations, because they have long been reported as highly efficient catalysts for carbon–carbon coupling and hydrogenation reactions . Our group has devoted much effort to developing ligand-stabilized metal nanoparticles for catalysis, and one of the nanosized catalysts, binaphthyl-palladium nanoparticles (denoted as Bin-PdNPs), was shown to be extremely active for selective hydrogenation of N-heteroaromatics. , A similar but larger nanocatalyst showed high activity in cross-coupling reactions, as well as in hydrogenation of aldehydes . Inspired by the aforementioned studies and our continuous works on allenylphosphine oxides, , we herein present a novel synthesis of Z and Z,Z -selective phosphinyl [3]­dendralenes catalyzed by Bin-PdNPs, proceeding with cascade alkynylation and highly selective hydrogenation.…”