Cyclopropanes. XVI. An Optically Active Grignard Reagent and the Mechanism of Grignard Formation

1964 ◽  
Vol 86 (16) ◽  
pp. 3288-3296 ◽  
Author(s):  
H. M. Walborsky ◽  
A. E. Young
Keyword(s):  
Grignard Reagent ◽  
Optically Active

Use of Menthyl 2-Methoxynaphthalene-1-sulfinates in the Andersen Synthesis of Optically Active Sulfoxides. Facile Cleavage by Grignard Reagents of Some Aromatic Methyl Ethers

1994 ◽  
Vol 47 (10) ◽  
pp. 1925 ◽  
Author(s):  
KH Bell ◽  
LF Mccaffery
Keyword(s):  
Grignard Reagent ◽  
Methoxy Group ◽  
Optically Active ◽  
Grignard Reagents ◽  
Sulfinyl Group

The pure crystalline diastereomers (1R,2S,5R)-menthyl (R)- and (S)-2-methoxynaphthalene-1-sulfinate (1b) have been prepared and, by reaction with Grignard reagents (the Andersen procedure), converted into optically active alkyl and aryl 2-methoxynaphthyl sulfoxides in 67-77% yields. Use of an excess of Grignard reagent results in facile O-alkyl cleavage of the methoxy group to the corresponding naphthol or a competing loss of the alkyl- or aryl- sulfinyl group to form 2-methoxynaphthalene. Pure diastereomers of menthyl 2,7- dimethoxynaphthalene-1-sulfinate (2b) and menthyl 4-methoxynaphthalene-1-sulfinate (3b) have also been prepared and their reactions with Grignard reagents have been studied.

THE REDUCTION, ENOLATE FORMATION, AND SOLVOLYSIS OF GRIGNARD REAGENTS IN OPTICALLY ACTIVE MEDIA

1957 ◽  
Vol 35 (8) ◽  
pp. 900-910 ◽  
Author(s):  
Norman Allentoff ◽  
George F Wright
Keyword(s):  
Grignard Reagent ◽  
Optically Active ◽  
Grignard Reagents ◽  
Inactive State ◽  
Active Media

The sec-butylbenzene produced by solvolysis of 2-phenyl-2-chlorobutane Grignard reagent in (+) 2,3-dimethoxybutane and benzene is optically inactive. The 2-↓-isopropyl-4-↑-methylcyclohexanols obtained by the reducing action of isopropyl Grignard reagent on racemic 2-↓-isopropyl-4-↑-methylcyclohexanone in (+) dimethoxybutane are optically active to the extent of 6 and 15%. The bromomagnesium enolates obtained by the action of isopropyl Grignard reagent on racemic 2-↓-isopropyl-4-↑-methylcyclohexanone in (+) dimethoxybutane regenerate the parent ketone in an optically inactive state but the diastereomeric 2-↑-isopropyl-4-↑-methylcyclohexanone also produced is optically active to the extent of about 6%.

Synthesis of optically active deacetyl anisomycin

1968 ◽  
Vol 46 (19) ◽  
pp. 3091-3094 ◽  
Author(s):  
C. M. Wong ◽  
J. Buccini ◽  
J. Te Raa
Keyword(s):  
Tartaric Acid ◽  
Grignard Reagent ◽  
Sodium Ethoxide ◽  
Phosphorus Pentachloride ◽  
Optically Active ◽  
Epoxide Ring ◽  
Hydride Reduction ◽  
Lithium Aluminium ◽  
Basic Hydrolysis ◽  
Layer Chromatography

Optically active (−)-deacetyl anisomycin and the enantiomer (+)-deacetyl anisomycin were synthesized starting with (+)-2R 3R tartaric acid. The asymmetric centers of the tartaric acid correspond to the C-2 and C-3 asymmetric centers of anisomycin. N-Benzyl tartarimide (3) was attacked by the Grignard reagent of anisyl chloride followed by lithium aluminium hydride reduction to give two diols (7) and (8) separated by thin-layer chromatography. The diol (8) was debenzylated giving the natural (−)-deacetyl anisomycin. The diol (7) was converted into the epoxide (10) by selective acetylation of the C-4 hydroxy group followed by treatments with phosphorus pentachloride and sodium ethoxide. Opening of the epoxide ring of 10 in boiling acetic acid followed by basic hydrolysis gave (+)-N-benzyl deacetyl anisomycin (11) which was debenzylated to give (+)-deacetyl anisomycin.

THE SIGNIFICANCE OF HALIDE IN GRIGNARD REAGENTS

1964 ◽  
Vol 42 (11) ◽  
pp. 2474-2479 ◽  
Author(s):  
Warren French ◽  
George F Wright
Keyword(s):  
Optical Activity ◽  
Magnesium Chloride ◽  
Grignard Reagent ◽  
Methyl Chloride ◽  
Optically Active ◽  
Grignard Reagents ◽  
The Difference

The optical activity of 1-phenylethanol from benzaldehyde and methyl chloride Grignard reagent coordinated with (+)2,3-dimethoxybutane is about one fourth of that found for the same product when bis-methylmagnesium is the reagent. The difference has been attributed to the relative coordinating power of magnesium chloride versus the optically active ether.

Optical analysis of ink and other contaminants in process waters

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 51-58
Author(s):  
ANTTI HAAPALA ◽  
MIKA KÖRKKÖ ◽  
ELISA KOIVURANTA ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Optically Active ◽  
Process Water ◽  
Paper Machine ◽  
Optical Analysis ◽  
Direct Process ◽  
Active Components ◽  
Water Contaminants ◽  
Dependent Measurement ◽  
Measurement Methodology

Analysis methods developed specifically to determine the presence of ink and other optically active components in paper machine white waters or other process effluents are not available. It is generally more interest¬ing to quantify the effect of circulation water contaminants on end products. This study compares optical techniques to quantify the dirt in process water by two methods for test media preparation and measurement: direct process water filtration on a membrane foil and low-grammage sheet formation. The results show that ink content values obtained from various analyses cannot be directly compared because of fundamental issues involving test media preparation and the varied methodologies used to formulate the results, which may be based on different sets of assumptions. The use of brightness, luminosity, and reflectance and the role of scattering measurements as a part of ink content analysis are discussed, along with fine materials retention and measurement media selection. The study concludes with practical tips for case-dependent measurement methodology selection.

Microscopic Structure of Er-Related Optically Active Centers in Si

2003 ◽  
Vol 770 ◽  
Author(s):  
H. Przybylinska ◽  
N. Q. Vinh ◽  
B.A. Andreev ◽  
Z. F. Krasil'nik ◽  
T. Gregorkiewicz
Keyword(s):  
Ground State ◽  
Photoluminescence Spectrum ◽  
Zeeman Effect ◽  
Optically Active ◽  
Single Type ◽  
Active Centers ◽  
Mbe Growth ◽  
Spectral Components ◽  
Er Doped ◽  
Successful Observation

AbstractA successful observation and analysis of the Zeeman effect on the near 1.54 μm photoluminescence spectrum in Er-doped crystalline MBE-grown silicon are reported. A clearly resolved splitting of 5 major spectral components was observed in magnetic fields up to 5.5 T. Based on the analysis of the data the symmetry of the dominant optically active center was conclusively established as orthorhombic I (C2v), with g‼≈18.4 and g⊥≈0 in the ground state. The fact that g⊥≈0 explains why EPR detection of Er-related optically active centers in silicon may be difficult. Preferential generation of a single type of an optically active Er-related center in MBE growth confirmed in this study is essential for photonic applications of Si:Er.

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