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.

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%.

Cyanoacrylate Inhibitors of the Hill Reaction V. The Effect of Chirality on Inhibitor Binding

1987 ◽  
Vol 42 (6) ◽  
pp. 684-689 ◽  
Author(s):  
John L. Huppatz ◽  
John N. Phillips
Keyword(s):  
Phenyl Ring ◽  
Alkyl Substituent ◽  
Receptor Site ◽  
Optically Active ◽  
Hill Reaction ◽  
Inhibitor Binding ◽  
Level Of Activity ◽  
The Difference ◽  
The Hill

Optically active α-methylbenzylamino 2-cyanoacrylic esters were synthesized and assayed as inhibitors of the Hill reaction in isolated pea chloroplast fragments. The 5-isomers were more potent inhibitors than the S-isomers with discriminations of from ten to greater than 100-fold being observed. A β-alkyl substituent in the cyanoacrylate molecule affected both the level of activity and the difference in activity between the isomers. An α,α-dimethylbenzylamino derivative was also active at about the same level as the corresponding α-methylbenzylamino racemate. This result could be explained in terms of the orientation of the phenyl ring in the receptor site. Replacement of the α-methylbenzylamino group by other α-alkyl and α-phenyl substituents had little effect on activity. However, an α-benzyl group was beneficial.

On the syntheses and the optical properties of optically active 2-pyrazoline compounds

1979 ◽  
Vol 57 (3) ◽  
pp. 360-366 ◽  
Author(s):  
Makoto Mukai ◽  
Takashi Miura ◽  
Masahiro Nanbu ◽  
Toshinobu Yoneda ◽  
Yohji Shindo
Keyword(s):  
Optical Properties ◽  
Optical Activity ◽  
Optically Active ◽  
Spectroscopic Techniques ◽  
Considerable Influence ◽  
Pyrazoline Ring

Optically active 2-pyrazolines were synthesized and their optical properties were studied using various spectroscopic techniques to investigate the effects of substituents at the 3 and 5 positions of the 2-pyrazoline ring on their optical activity. It was found that in the case of 5-substituted-1,3-diphenyl-2-pyrazoline derivatives, the substituent at the 5 position has considerable influence on the optical activity, whereas in 3-substituted-1,5-diphenyl-2-pyrazoline derivatives, the substituent at the 3 position has no such influence.

scholarly journals Enhanced gyrotropic birefringence and natural optical activity on electromagnon resonance in a helimagnet

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. Iguchi ◽  
R. Masuda ◽  
S. Seki ◽  
Y. Tokura ◽  
Y. Takahashi
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Optical Activity ◽  
Optical Rotation ◽  
Magnetoelectric Coupling ◽  
Optically Active ◽  
Crystalline Solid ◽  
Spin Order ◽  
Active Devices ◽  
Principal Axes

AbstractSpontaneous symmetry breaking in crystalline solid often produces exotic nonreciprocal phenomena. As one such example, the unconventional optical rotation with nonreciprocity, which is termed gyrotropic birefringence, is expected to emerge from the magnetoelectric coupling. However, the fundamental nature of gyrotropic birefringence remains to be examined. Here w`e demonstrate the gyrotropic birefringence enhanced by the dynamical magnetoelectric coupling on the electrically active magnon resonance, i.e. electromagnon, in a multiferroic helimagnet. The helical spin order having both polarity and chirality is found to cause the giant gyrotropic birefringence in addition to the conventional gyrotropy, i.e. natural optical activity. It is demonstrated that the optical rotation of gyrotropic birefringence can be viewed as the nonreciprocal rotation of the optical principal axes, while the crystallographic and magnetic anisotropies are intact. The independent control of the nonreciprocal linear (gyrotropic birefringence) and circular (natural optical activity) birefringence/dichroism paves a way for the optically active devices.

The addition of organometallic reagents to tetramesityldigermene

2002 ◽  
Vol 80 (11) ◽  
pp. 1387-1392 ◽  
Author(s):  
Kyle L Fujdala ◽  
David W.K Gracey ◽  
Erica F Wong ◽  
Kim M Baines
Keyword(s):  
Ligand Exchange ◽  
Grignard Reagent ◽  
Thermal Conditions ◽  
Grignard Reagents ◽  
Ethylmagnesium Bromide ◽  
Organometallic Reagent ◽  
Organometallic Reagents ◽  
Thermal Cleavage

The thermolysis and photolysis of hexamesitylcyclotrigermane in the presence of ethylmagnesium bromide has been investigated. Under photochemical conditions, ethyldimesitylgermane, 1,2-diethyl-1,1,2-trimesityldigermane and ethyl-1,1,2,2-tetramesityldigermane were isolated and, under thermal conditions, 1,2,2-triethyl-1,1-dimesityl digermane and 2,2-diethyl-1,1,1-trimesityldigermane were isolated. The photolysis of hexamesitylcyclotrigermane in the presence of methyllithium has also been investigated. In both cases, the organometallic reagent adds to tetramesityl digermene and dimesitylgermylene formed by photochemical or thermal cleavage of the cyclotrigermane. In the case of the addition of the Grignard reagent, the resulting germyl Grignard reagent undergoes a facile ligand exchange reaction.Key words: digermene, germylene, Grignard reagents, alkyllithium reagents, germylmagnesium compounds, germyllithium compounds.

Sign in / Sign up

Export Citation Format

Share Document