53432-38-5

Upstream product

• 2000-43-3 2,2,2-trichloro-1-phenylethanol 
• 2902-69-4 2,2,2-trichloroacetophenone 
• 100-52-7 benzaldehyde 

Downstream Products

• 1644186-27-5 C₉H₈Cl₃NO₃ 

Relevant academic research and scientific papers

London Dispersion Interactions Rather than Steric Hindrance Determine the Enantioselectivity of the Corey–Bakshi–Shibata Reduction

The well-known Corey–Bakshi–Shibata (CBS) reduction is a powerful method for the asymmetric synthesis of alcohols from prochiral ketones, often featuring high yields and excellent selectivities. While steric repulsion has been regarded as the key director of the observed high enantioselectivity for many years, we show that London dispersion (LD) interactions are at least as important for enantiodiscrimination. We exemplify this through a combination of detailed computational and experimental studies for a series of modified CBS catalysts equipped with dispersion energy donors (DEDs) in the catalysts and the substrates. Our results demonstrate that attractive LD interactions between the catalyst and the substrate, rather than steric repulsion, determine the selectivity. As a key outcome of our study, we were able to improve the catalyst design for some challenging CBS reductions.

Rhodium-catalyzed stereoselective amination of thioethers with n-mesyloxycarbamates: DMAP and Bis(DMAP)CH2Cl2 as key additives

A stereoselective Rh-catalyzed intermolecular amination of thioethers using a readily available chiral N-mesyloxycarbamate to produce sulfilimines in excellent yields and diastereomeric ratio is described. A catalytic mixture of 4-dimethylaminopyridine (DMAP) and bis(DMAP)CH2Cl2 proved pivotal in achieving high selectivity. The X-ray crystal structure of the (DMAP)2·[Rh2{(S)-nttl}4] complex was obtained and mechanistic studies suggested a RhII-RhIII complex as the catalytically active species.

Trichloromethyl ketones: Asymmetric transfer hydrogenation and subsequent Jocic-type reactions with amines

Amino-amides are important pharmaceutical building-blocks. The enantioselective reduction of trichloromethyl ketones using ruthenium transfer hydrogenation catalysts is reported. The products react in a range of Jocic-type reactions to give enantiomerically enriched amino-amides.

Solution-phase synthesis and evaluation of tetraproline chiral stationary phases

A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright

The influence of fluorine on the asymmetric reduction of fluoromethyl ketones

A comparative study of the asymmetric reduction of representative aryl and alkyl α-fluoro- and α-chloromethyl ketones using (-)-diisopinocampheylchloroborane [(-)-DIP-Chloride] and (-)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane [R-Alpine-Borane] has been made. It was observed that DIP-Chloride is superior in terms of the rate and enantioselectivity for both classes of halo-ketones. While the reduction of monofluoroacetone and trifluoroacetone with DIP-Chloride provided the product alcohols in 61% ee and 96% ee, respectively, the reduction of difluoroacetone yielded only 5% ee. The influence of a lone halogen atom was not observed for monochloroacetone, all of which point towards a chelating effect of monofluoroacetone on the Lewis acidic chloroborane.

Catalytic enantioselective synthesis of secondary alcohols using C2-symmetric diamino diol ligands

A new class of diamino diols was evaluated as catalytic ligands in the enantioselective borane reduction of aromatic ketones and the enantioselective ethylation of arylaldehydes with diethylzinc. By variation of the substitution pattern on the ketone, e.e.s of up to 94% could be obtained by in situ borane reduction using 0.025 equiv. of the ligand at 35°C in THF. N,N,N′,N′-Tetramethyldiamino diol and N,N′-dialkyl diamino diol were used as promoters for the enantioselective addition of diethylzinc reagent to the arylaldehyde, where use of 0.1 equiv. of N,N,N′,N′-tetramethyl diamino diol as catalyst in the addition of diethylzinc to arylaldehyde achieved e.e.s of up to 98%.

β-Hydroxysulfoximines in the catalyzed enantioselective reduction of ketones with borane

Optically active β-hydroxysulfoximines catalyze the asymmetric borane reduction of ketones affording secondary alcohols in high yields with good enantioselectivities (up to 93% ee).

A NEW PREPARATIVE METHOD FOR OPTICALLY ACTIVE DIARYLCARBINOLS

Some diarylcarbinols were resolved efficiently by complexation with brucine.

Optical Resolution of Tertiary Acetylenic Alcohols and Secondary Alcohols by Complexation with Achiral Amines

Partially resolved tertiary acetylenic alcohols and secondary alcohols were easily resolved completely by complexation with achiral amines such as 1,4-diazabicyclooctane (DABCO), N,N'-dialkylpiperazine, N,N,N',N'-tetramethylethylenediamine, and pyrazine, to give optically pure enantiomers.Interestingly, DABCO formed more stable complex with optically pure enantiomers but the other amines formed more stable complex with racemic compounds.