An Effective and Useful Synthesis of Enantiomerically Enriched Arylglycinols

Bandini, Marco; Cozzi, Pier Giorgio; Gazzano, Massimo; Umani‐Ronchi, Achille

doi:10.1002/1099-0690(200105)2001:10<1937::aid-ejoc1937>3.0.co;2-2

Cited by 9 publications

(6 citation statements)

References 38 publications

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“…In an attempt to overcome this issue, we have investigated more sterically encumbered chiral auxiliaries to improve the selectivity in acetate aldol additions of chlorotitanium enolates of N -acetylthiazolidinethiones. Mesityl-substituted oxazolidinethione and thiazolidinethiones were chosen due to the restricted rotational freedom about the bond between the aromatic ring and the benzylic carbon …”

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confidence: 99%

Highly Selective Acetate Aldol Additions Using Mesityl-Substituted Chiral Auxiliaries

Crimmins

Shamszad

2006

Org. Lett.

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[reaction: see text] Highly diastereoselective acetate aldol additions using chlorotitanium enolates of mesityl-substituted N-acetyloxazolidinethione and N-acetylthiazolidinethione auxiliaries are reported. These additions proceed in high yields and diastereoselectivities (93:7 to 98:2) for aliphatic, aromatic, and ,-unsaturated aldehydes. Double diastereoselective acetate aldol additions are also reported and are found to proceed in high yields and diastereoselectivities (90:10 to 97:3).

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confidence: 99%

Highly Selective Acetate Aldol Additions Using Mesityl-Substituted Chiral Auxiliaries

Crimmins

Shamszad

2006

Org. Lett.

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“…The synthetic scheme for the ligand 6 and complexes 1a and 1b is shown in Figure . The racemic aminoethanol derivative 4 was synthesized via the dihydroxylation of pentafluorostyrene ( 2 ) followed by the Ritter rearrangement of 3 . Subsequent ZnCl 2 -catalyzed condensation with the commercial benzonitrile derivative 5 afforded racemic 6 in 41% yield.…”

Section: Resultsmentioning

confidence: 99%

“…The racemic aminoethanol derivative 4 was synthesized via the dihydroxylation of pentafluorostyrene (2) followed by the Ritter rearrangement of 3. 46 Subsequent ZnCl 2 -catalyzed condensation with the commercial benzonitrile derivative 5 afforded racemic 6 in 41% yield. Reaction of 6 with the racemic dimeric complex [Ir(dfppy) 2 (μ-Cl)] 2 resulted in near-quantitative conversion to the diastereomers 1a and 1b, which were each formed as a racemic pair of enantiomers.…”

Section: ■ Introductionmentioning

confidence: 99%

Intramolecular π–π Interactions with a Chiral Auxiliary Ligand Control Diastereoselectivity in a Cyclometalated Ir(III) Complex

Congrave

Batsanov

et al. 2018

Inorg. Chem.

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The application of a chiral auxiliary ligand to control the diastereoselectivity in the synthesis of a cyclometalated iridium(III) complex is presented. The diastereomeric iridium(III) complexes 1a and 1b are reported in which a phenoxyoxazoline auxiliary ligand incorporates a chiral center functionalized with a pendant pentafluorophenyl group. The diastereomers were readily separated and their structural, electrochemical and photophysical properties are discussed. Solution-state NMR data and X-ray crystal structures establish that the pentafluorophenyl group engages in intramolecular π-π interactions. The X-ray analysis reveals that the two diastereomers display very different modes of intramolecular stacking. The variable temperature 19 F NMR data indicate that rotation of the pendant pentafluorophenyl rings in 1b and 1a is a temperature dependent process, and that there is a smaller energy barrier to rotation in 1b compared to 1a. This correlates with variable temperature photoluminescence data which show that upon heating the integrated emission intensity is reduced substantially more for 1b than for 1a, which is ascribed to the enhanced rotation in 1b providing a more easily populated non-radiative pathway compared to 1a. These experimental data are supported by computational calculations. Phosphorescent organic light emitting devices (PhOLEDs) using 1a as the dopant complex give blue-green emission with a high maximum external quantum efficiency (EQE max ) of 25.8% (at ca. 270 cd m −2 ) and with a low efficiency rolloff to 24.9% at 1000 cd m −2 . Our results extend the scope of ligand design for cyclometalated iridium complexes which possess interesting structural and emission properties.

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“…Alcohol 1 was also used to produce amine 2 used for the synthesis of the series of amide, urea and sulfonamide derivatives (5,7,8), respectively. Conversion of 1 to the corresponding acetamide via a Ritter reaction (Scheme 1), 21,22 using acetonitrile as the nitrogen source, and subsequent hydrolysis in refluxing 6 M HCl afforded the primary amine 2 in excellent yield (>99% over three steps).…”

Section: Resultsmentioning

confidence: 99%

Novel Potent and Efficacious Nonpeptidic Urotensin II Receptor Agonists

et al. 2006

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Six different series of nonpeptidic urotensin II receptor agonists have been synthesized and evaluated for their agonistic activity in a cell-based assay (R-SAT). The compounds are ring-opened analogues of the isochromanone-based agonist AC-7954 with different functionalities constituting the linker between the two aromatic ring moieties. Several of the compounds are highly potent and efficacious, with N-[1-(4-chlorophenyl)-3-(dimethylamino)-propyl]-4-phenylbenzamide oxalate (5d) being the most potent. The pure enantiomers of 5d were obtained from the corresponding diastereomeric amides. It was shown by a combination of X-ray crystallography and chemical correlation that the activity resides in the S-enantiomer of 5d (pEC(50) 7.49).

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An Effective and Useful Synthesis of Enantiomerically Enriched Arylglycinols

Cited by 9 publications

References 38 publications

Highly Selective Acetate Aldol Additions Using Mesityl-Substituted Chiral Auxiliaries

Highly Selective Acetate Aldol Additions Using Mesityl-Substituted Chiral Auxiliaries

Intramolecular π–π Interactions with a Chiral Auxiliary Ligand Control Diastereoselectivity in a Cyclometalated Ir(III) Complex

Novel Potent and Efficacious Nonpeptidic Urotensin II Receptor Agonists

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