214976-78-0

Upstream product

• 37942-07-7 3,5-di-tert-butyl-2-hydroxybenzaldehyde 
• 29841-69-8 (S,S)-1,2-diphenyl-1,2-diaminoethane 
• 84210-37-7 3,5-di-tert-butyl-salicylaldehyde 

Relevant academic research and scientific papers

Visible Light-Induced Salan-Copper(II)-Catalyzed Enantioselective Aerobic α-Hydroxylation of β-Keto Esters

A strategy of visible light-induced salan-copper(II)-catalyzed asymmetric α-hydroxylation of β-keto ester with utilization of sustainable air as the oxidant was developed. This protocol allows convenient access to a number of enantioenriched α-hydroxyl β-keto esters (up to 95% yield, 96% ee), especially for β-keto methyl esters that are valuable architectures in pharmaceuticals, including the key intermediate of the sodium-channel blocker (S)-indoxacarb. Experimental studies suggest that reactive singlet oxygen may participate in this reaction. (Figure presented.).

Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes

New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).

Enantioselective α-Hydroxylation by Modified Salen-Zirconium(IV)-Catalyzed Oxidation of β-Keto Esters

The highly enantioselective α-hydroxylation of β-keto esters using cumene hydroperoxide (CHP) as the oxidant was realized by a chiral (1S,2S)-cyclohexanediamine backbone salen-zirconium(IV) complex as the catalyst. A variety of corresponding chiral α-hydroxy β-keto esters were obtained in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). The zirconium-catalyzed enantioselective α-hydroxylation of β-keto esters was scalable, and the zirconium catalyst was recyclable. The reaction can be performed in gram scale, and corresponding chiral products were acquired in 95% yield and 99% ee.

Group 4 metal complexes with new chiral pincer NHC-ligands: Synthesis, structure and catalytic activity

Chiral group 4 NHC-metal complexes were prepared in good yields by amine elimination from M(NR2)4 (M = Ti, Zr, Hf; R = Me, Et) and chiral pincer NHC-ligands, L4 (L4a and L4b), L5 and L6, which are derived from (S,S)-diphenyl-1,2-ethanediamine. Treatment of M(NR2)4 with 1 equiv. of L4 in THF gives, after recrystallization from a benzene solution, the chiral titanium amides (L4)Ti(NMe2)(Br)(THF) (7) and (L4)Ti(NMe2)(Cl)(THF) (11), zirconium amides (L4)Zr(NMe 2)(Br)(THF) (8), (L4)Zr(NEt2)(Br)(THF) (10), (L4)Zr(NMe2)(Cl)(THF) (12) and (L4)Zr(NEt2)(Cl)(THF) (14), and hafnium amides (L4)Hf(NMe2)(Br)(THF) (9) and (L4)Hf(NMe 2)(Cl)(THF) (13), respectively. Similarly, the reactions of L5 or L6 with 1 equiv. of M(NR2)4 yield the titanium amide (L6)Ti(NMe2)(Cl)(THF) (16), the zirconium amides (L5)Zr(NMe 2)(Cl)(THF) (15), (L6)Zr(NMe2)(Cl)(THF) (17) and (L6)Zr(NEt2)(Cl)(THF) (19), and the hafnium amide (L6)Hf(NMe 2)(Cl)(THF) (18), respectively. Complexes 7-19 were characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 10 and 14-19 were also established by X-ray diffraction analyses, which represent the first example of the structurally characterized group 4 chiral NHC-metal complex. Furthermore, 7-19 are active catalysts for the polymerization of rac-lactide in the presence of isopropanol, leading to the heterotactic-rich polylactides. the Partner Organisations 2014.

Asymmetric epoxidation of unfunctionalized alkenes with ammonium and phosphonium monopersulfates catalyzed by chiral Mn(III)-salen complexes

Simple cis-disubstituted and trisubstituted alkenes were enantioselectively epoxidized in mild conditions using various Mn(III)-salen complexes as catalysts and quaternary ammonium and phosphonium monopersulfates (Bu4NHSO5, Ph4