Application of phosphorylated reagents derived from N,N′-di-[(S)-α-phenylethyl]-cyclohexane-1,2-diamines in the determination of the enantiomeric purity of chiral alcohols

Chiral Tertiary Amine/L‐Proline Cocatalyzed Enantioselective Morita–Baylis–Hillman (MBH) Reaction

“…In accord with Juaristic and coworkers' procedure, [11] the ring-opening of cyclohexene oxide readily took place in the presence of anhydrous lithium perchlorate. The corresponding diastereomeric 2-aminocyclohexanols 6a (minor, 24 %) and 6b (major, 57 %) were separated by column chromatography on silica gel.…”

Chiral 1,2-Amino Alcohols and 1,2-Diamines Derived from Cyclohexene Oxide: Recent Applications in Asymmetric Synthesis

“…53 With enantiopure trans-N,N¢-di [1-phenylethyl]cyclohexane-1,2-diamines 100 and 101 at hand, and inspired by the work of Alexakis and coworkers 54 we proceeded to examine these chiral diamines as potential CDAs via their corresponding P-chloro-1,3-diazaphospholidines. 46 To this end, 1,2-diamines 100 and 101 in CDCl 3 solvent (NMR lock signal) was treated with PCl 3 (1 equiv) and diethylaniline (1 equiv) in CH 2 Cl 2 to give the required phospholidines 124 and 125. The exocyclic P-Cl bond is readily cleaved, 54 so derivatization was carried out directly in the NMR tube by addition of 0.8 equivalents of the racemic alcohol to afford phosphonamides 126 and 127, whose 31 P NMR were then recorded (Table 7).…”

“…The exocyclic P-Cl bond is readily cleaved, 54 so derivatization was carried out directly in the NMR tube by addition of 0.8 equivalents of the racemic alcohol to afford phosphonamides 126 and 127, whose 31 P NMR were then recorded (Table 7). 46 The NMR spectroscopic observations summarized in Table 7 reveal the effectiveness of the chlorophospholidines 124 and 125 for the determination of enantiomeric ratios in mixtures of chiral alcohols. The diastereomeric pairs of derivatives 126 and 127 were always observed, and integration of the signals corresponded to the expected 50:50 ratio; i.e., no kinetic resolution took place.…”

“…58 Furthermore, Anaya de Parrodi and Walsh probed the nature of the chiral diamine backbone by preparing an analogous bis(sulfonamide) diol ligand 134 derived from trans-1,2-diaminocyclopentane 132 46. …”

Determination of the enantiomeric excess of chiral carboxylic acids by 31P NMR with phosphorylated derivatizing agents from C2‐symmetrical diamines containing the (S)‐α‐phenylethyl group

“…8 Pioneering work for the determination of enantiomeric purity of carboxylic acids using other nucleus was reported early in the 80s and 90s. [9][10][11] In contrast, there are numerous reports of organophosphorus diamine CDAs employed for the determination of enantiomeric purity of chiral alcohols, thiols, and amines by 31 P NMR, [12][13][14][15][16][17][18][19][20][21] but relatively few reports analyzing the enantiopurity of chiral carboxylic acids have been published. [22][23][24] In this regard, we describe the preparation of C 2 symmetric diamines 1-4 ( Fig.…”