Resolution and configuration of .alpha.-substituted phenylacetic acids

Aaron, Colin; Dull, David L.; Schmiegel, Joel L.; Jaeger, David A.; Ohashi, Yoko; Mosher, Harry S.

doi:10.1021/jo01284a035

Cited by 64 publications

(9 citation statements)

References 2 publications

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“…This reaction afforded substituted phenylacetic acids 35 and 36 (15) for which optical rotation values were compared with previously reported ones. As it turned out, the major enantiomer obtained for product 36 issued from alkylation in toluene or ether had the "Sn configuration.…”

Section: Kylations Of This Compound With Methyl Iodide In Ether Ormentioning

confidence: 86%

Chiral organosilicon compounds in synthesis. Preparation and stereoselective alkylations of silylcinnamyl carbanions

Lamothe¹,

Cook²,

Chan³

1992

Can. J. Chem.

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Silylallyl carbanions of type 13 bearing a chiral lithium complexing substituent remote from silicon can be alkylated regio- and stereoselectively at the α-position by small electrophiles in nonpolar solvents. The regiochemical outcome of the reaction was found to be highly dependent on the size of the incoming electrophile. Secondary alkyl halides react preferentially at the γ-center and good levels of stereoselectivity are still obtained in nonpolar solvents despite the rather long distance between the reacting center and the chiral auxiliary. Transformation of the alkylated allylsilanes into optically active alcohols and carboxylic acids may represent a potential synthetic application of the method.

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Section: Kylations Of This Compound With Methyl Iodide In Ether Ormentioning

confidence: 86%

Chiral organosilicon compounds in synthesis. Preparation and stereoselective alkylations of silylcinnamyl carbanions

Lamothe¹,

Cook²,

Chan³

1992

Can. J. Chem.

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“…1 2-(4-Hydroxyphenyl)butanoic Acid (12). Following the procedure by Aaron (39), sodium (1.58 g, 69.2 mmol) was added to a solution of naphthalene (8.87 g, 69.2 mmol) in THF (60 mL) and was stirred for 4 h with occasional sonication, during which time it turned the characteristic deep blue color. This was added to a solution of 4-methoxyphenylacetic acid (5.00 g, 30.1 mmol) in THF (70 mL) dropwise, which was then stirred for several h. The reaction was then cooled in an ice bath, and to it, EtBr (2.56 mL, 34.3 mmol) was added dropwise.…”

Section: Methodsmentioning

confidence: 99%

Integrated “3+1” Oxorhenium(V) Complexes as Estrogen Mimics

Skaddan

Katzenellenbogen

1998

Bioconjugate Chem.

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The diagnosis and staging of breast cancer could be improved by the development of imaging radiopharmaceuticals that provide a noninvasive determination of the estrogen receptor (ER) status of tumor cells. Toward this goal, we have synthesized a number of integrated "3+1" oxorhenium(V) complexes designed to mimic estradiol and a class of nonsteroidal estrogens, the tetrahydrochrysenes (THC). The monodentate component of the estradiol mimic is a p-hydroxyphenethyl thiol ligand with ethyl substituents at the benzylic and homobenzylic positions. Model complexes of this ligand were easily made, but steric hindrance of the secondary thiol prevented the formation of the complex with the disubstituted ligand. The three "3+1" oxorhenium(V) complexes prepared to mimic the THC class mimics represent the first pyridinedithiol rhenium complexes of their kind to be made. These complexes are quite stable to air and moisture. The target tridentate ligand was prepared from chelidamic acid, and the VT NMR of the rhenium complex displays interesting fluxional behavior. The binding affinities of these complexes for the estrogen receptor are low, and their lipophilicities are rather high. Nevertheless, our findings provide a further refinement of our understanding of ligand structure-binding affinity correlations for the estrogen receptor.

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“…This racemic carboxylic acid 46 can be converted into the ammonium salts of (-)-or (+)-1-phenylethylamine, 47 and then carried out by their fractional recrystallization from EtOH/H 2 O to afford (R)-(-)-or (S)-(+)--(trifluoromethyl) phenyl acetic acid 48 in a pure form (Scheme 14) [64].…”

Section: Resolution Of Racemic Compoundmentioning

confidence: 99%