191090-38-7Relevant articles and documents
Synthesis and application of N-3,5-dinitrobenzoyl and C3 symmetric diastereomeric chiral stationary phases
Ryoo, Jae Jeong,Yu, Jeong Jae
, (2022/01/20)
Three diastereomeric chiral compounds, namely, (R,R)-(+)-2-amino-1,2-diphenylethanol, (1S,2R)-(+)-2-amino-1,2-diphenylethanol, and (1R,2R)-(+)-1,2-diphenylethylenediamine were used as starting materials for preparing three N-3,5-dinitrobenzoyl derivative
Synthesis of new C3 symmetric amino acid- and aminoalcohol-containing chiral stationary phases and application to HPLC enantioseparations
Yu, Jeongjae,Armstrong, Daniel W.,Ryoo, Jae Jeong
, p. 74 - 84 (2017/12/26)
We recently reported a new C3-symmetric (R)-phenylglycinol N-1,3,5-benzenetricarboxylic acid-derived chiral high-performance liquid chromatography (HPLC) stationary phase (CSP 1) that demonstrated better results as compared to a previously described N-3,5-dintrobenzoyl (DNB) (R)-phenylglycinol-derived CSP. Over a decade ago, (S)-leucinol, (R)-phenylglycine, and (S)-leucine derivatives were used as the starting materials of 3,5-DNB-based Pirkle-type CSPs for chiral separation. In this study, three new C3-symmetric CSPs (CSP 2, 3, and 4) were prepared by combining the ideas and results mentioned above. Here we describe the synthetic procedures and applications of the new C3-symmetric CSPs (CSP 2–CSP 4).
SuperQuat N-acyl-5,5-dimethyloxazolidin-2-ones for the asymmetric synthesis of α-alkyl and β-alkyl aldehydes
Bull, Steven D.,Davies, Stephen G.,Nicholson, Rebecca L.,Sanganee, Hitesh J.,Smith, Andrew D.
, p. 2886 - 2899 (2007/10/03)
The proclivity of α-branched N-2′-benzyl-3′-phenylpropionyl derivatives of (S)-4-benzyl-5,5-dimethyl-, (S)-4-phenyl-5,5-dimethyl-, (S)-4-isopropyl-5,5-dimethyl-, (S)-4-benzyl- and (S)-4-benzyl-5,5-diphenyl-oxazolidin-2-ones to generate directly 2-benzyl-3-phenylpropionaldehyde upon hydride reduction with DIBAL is investigated. The (S)-4-benzyl-5,5-dimethyl-derivative proved optimal for inhibition of endocyclic nucleophilic attack, giving 2-benzyl-3-phenylpropionaldehyde in good yield upon reduction. Application of this methodology for the asymmetric synthesis of chiral aldehydes via diastereoselective enolate alkylation of a range of (S)-N-acyl-4-benzyl-5,5-dimethyloxazolidin-2-ones to afford an array of α-substituted-N-acyl-5,5-dimethyloxazolidin-2-ones (85-94% de) and subsequent reduction with DIBAL afforded directly non-racemic α-substituted aldehydes without loss of stereochemical integrity (87-94% ee). The extension of this protocol for the asymmetric synthesis of β-substituted aldehydes is demonstrated, via the diastereoselective conjugate addition of a range of organocuprates to (S)-N-acyl-4-phenyl-5,5-dimethyloxazolidin-2-ones which proceeds with high diastereoselectivity (generally >95% de). Reduction of the conjugate addition products with DIBAL gives non-racemic β-substituted aldehydes in high yields and in high ee (generally >95% ee). This methodology is exemplified by the asymmetric synthesis of (R)-3-isopropenylhept-6-enal, which has previously been used in the synthesis of (3Z,6R)-3-methyl-6-isopropenyl-3,9-decadien-1-yl acetate, a component of the sex pheromones of the California red scale.
A short synthesis of (S)-α-(diphenylmethyl)alkyl amines from amino acids
O'Hagan, David,Tavasli, Mustafa
, p. 1189 - 1192 (2007/10/03)
A range of (S)-α-(diphenylmethyl)alkyl amines were prepared from the corresponding (S)-α-amino acid ester hydrochlorides. These amines were derived by direct hydrogenation of their precursor oxazolidinones.
A useful modification of the Evans auxiliary: 4-Isopropyl-5,5- diphenyloxazolidin-2-one
Hintermann, Tobias,Seebach, Dieter
, p. 2093 - 2126 (2007/10/03)
The 4-isopropyl-5,5-diphenyloxazolidinone (1) is readily prepared from (R)- or (S)-valine ester, PhMgBr, and ethyl chlorocarbonate. It has a melting point of ca. 250°, a low solubility in most organic solvents, and a C=O group which is sterically protected from nucleophilic attack. Thus, the soluble N-acyl-oxazolidinones (7-16) can be prepared from 1 with BuLi at temperatures around 0°instead of - 78°(Scheme 3), their Li enolates can be generated with BuLi, rather than with LDA, and deacylation in the final step of the procedure can be achieved with NaOH at ambient temperatures (Scheme 12), with facile recovery of the precipitating auxiliary 1 (filtering, washing, and drying). The following reactions of N-acyl-oxazolidinones from 1 have been investigated: alkylations (Scheme 4), aminomethylations and hydroxymethylations (Scheme 5), aldol additions (Schemes 6 and 7), Michael additions (Schemes 9 and 10), and a (4 + 2) cycloaddition (Scheme 11). The well-known features of reactions following the Evans methodology (yield, diastereoselectivity, dependence on conditions, counter ions, additives etc.) prevail in these transformations. Most products, however, have higher melting points and a much more pronounced crystallization tendency than those derived from conventional oxazolidinones, and can thus be purified by recrystallization, avoiding chromatography (Table 1). The disadvantage of 1 having a higher molecular weight (ca. 150 Da) than the non-phenyl-substituted auxiliary is more than compensated by the ease of its application, especially on large scale. A number of crystal structures of oxazolidinones derived from 1 and a TiCl4 complex of an oxazolidinone are described and discussed in view of the diastereoselective-reaction mechanisms.
