853647-40-2

Upstream product

• 853647-38-8 (4S)-3-[(3R)-3-(p-fluorophenyl)butanoyl]-4-isopropyl-1,3-oxazolan-2-one 
• 29123-91-9 3-(4-fluorophenyl)-3-buten-1-ol 
• 147471-19-0 (E)-3-(4-fluorophenyl)-2-butenoic acid ethyl ester 
• 853647-35-5 C₁₅H₁₉FO₃ 
• 162549-00-0 4-fluoro-β-methylbenzenepropanoic acid ethyl ester 
• 403-42-9 1-(4-fluorophenyl)ethanone 

Downstream Products

• 853647-57-1 (3R)-1-deuterio-3-(p-fluorophenyl)butane 
• 853647-42-4 (3R)-3-(p-fluorophenyl)butyl 4-methyl-1-benzenesulfonate 

Relevant academic research and scientific papers

Helical triskelion monophosphites as ligands in asymmetric catalysis

Members of a new family of chiral triskelion P ligands, namely helical C3-symmetric monophos- phites P(OR)3, have been prepared in two steps Dy monoacylation of (R)- or (S)-1,1'-binaphthyl-2,2'-diol (BINOL) or diphenol using a carboxylic acid chloride followed Dy PCl3 phosphorylation. The most sterically hindered member of these monophosphites, derived from the compound accessible by monoacylation of BINOL using adamantane carboxylic acid chloride, has been characterized by X-ray crystallography and NMR spectroscopy as a single well-defined compound. It exists exclusively in the syn conformation, with a propeller-like (twisted) geometry resulting in helicity. Upon utilization of(R)- or (S)-BINOL in the two-step synthesis, the helicity proves to be P or M, respectively. When used as ligands in the Rh-catalyzed asymmetri c hydrogenation of prochiral homoallylic alcohols, these bulky helical ligands lead to respectable enantioselectivities (79-98percent ee). In contrast, the less sterically congested and more flexible BINOL-derived phenyl analogue exists in several conformeric forms, even in the crystal, and this leads to poor enantioselectivity in the model reactions (ee = 32percent). For the purpose of structural comparison, the analogous monophosphites derived from diphenol were also prepared and characterized. These compounds, again in contrast to the BINOL-derived adamantyl derivatives, occur in several different conformeric states.

Crucial role of elusive isomeric η-complexes in gas-phase electrophilic aromatic alkylations

The kinetics and stereochemistry of the protonation-induced unimolecular isomerization of (R)-1-D1-3-(p-fluorophenyl)butane have been investigated in the gas phase at 40-100 °C and 70-760 Torr. This process leads to the formation of the relevant meta and ortho isomers with partial racemization of the migrating sec-butyl moiety. Complete racemization is observed, instead, when the isomerization reaction involves a 1,2-H shift in the moving alkyl group. These results, together with the relevant activation parameters, fully confirm the previous evidence of the occurrence in the alkyl cation/arene PES of noncovalent η-type intermediates of defined structure and stability, lying well below the classical π-complexes, as confirmed by ab initio calculations. Their crucial role in determining the positional selectivity of gas-phase electrophilic aromatic substitutions clearly emerges from the comparison of the present results with the site selectivity measured in the corresponding bimolecular arene alkylation carried out at the same temperatures and pressures.