Endoperoxidation of 9,10-Bis(1-hydroxyalkyl)anthracenes and Successive Formation of 9,10-Anthraquinone under Grignard Reaction Conditions.

ChemInform ◽  
2004 ◽  
Vol 35 (19) ◽  
Author(s):  
Shigeyasu Kuroda ◽  
Mitsunori Oda ◽  
Hiroki Syumiya ◽  
Shah M. I. Shaheen ◽  
Ryuta Miyatake ◽  
...  
Keyword(s):  
Grignard Reaction ◽  
Reaction Conditions ◽  
Successive Formation

Endoperoxidation of 9,10-Bis-(1-hydroxyalkyl)anthracenes and Successive Formation of 9,10-Anthraquinone under Grignard Reaction Conditions

Heterocycles ◽  
2004 ◽  
Vol 62 (1) ◽  
pp. 153 ◽  
Author(s):  
Shigeyasu Kuroda ◽  
Mitsunori Oda ◽  
Hiroki Syumiya ◽  
Shah M. I. Shaheen ◽  
Ryuta Miyatake ◽  
...  
Keyword(s):  
Grignard Reaction ◽  
Reaction Conditions ◽  
Successive Formation

Stereospecific Grignard reactions of cholesteryl 1-alkenesulfinate esters: Application of the Andersen Protocol to the preparation of non-racemic α,β-unsaturated sulfoxides

2003 ◽  
Vol 81 (6) ◽  
pp. 423-430 ◽  
Author(s):  
Rick R Strickler ◽  
John M Motto ◽  
Craig C Humber ◽  
Adrian L Schwan
Keyword(s):  
Ester Group ◽  
Grignard Reagents ◽  
Grignard Reaction ◽  
Substitution Reactions ◽  
Reaction Conditions ◽  
Enantiomerically Pure ◽  
Sulfinate Esters ◽  
Grignard Reactions

Enantiomerically enriched α,β-unsaturated sulfinate esters of (–)-cholesterol undergo stereospecific substitutions at sulfur when treated in benzene at 6°C with Grignard reagents. Sulfoxides with ees of 85–99.5% are obtained when enantiopure sulfinates are used. The substitution reactions proceed with inversion of sulfur configuration. Enantiomerically pure cholesteryl (E)-2-carbomethoxyethenesulfinate is not a suitable reactant under the Grignard reaction conditions. It is suggested that the ester group induces unwanted reactions significantly lowering both the yield and sulfur stereogenicity.Key words: sulfinate, sulfoxide, Grignard reagents, stereospecific, unsaturated.

scholarly journals Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

2014 ◽  
Vol 10 ◽  
pp. 1942-1950 ◽  
Author(s):  
Maroš Bella ◽  
Bohumil Steiner ◽  
Vratislav Langer ◽  
Miroslav Koóš
Keyword(s):  
Spectral Data ◽  
Crystallographic Analysis ◽  
Grignard Reaction ◽  
Reaction Conditions ◽  
X Ray

The Grignard reaction of 2,3-O-isopropylidene-α-D-lyxo-pentodialdo-1,4-furanoside and benzylmagnesium chloride (or bromide) afforded a non-separable mixture of diastereomeric benzyl carbinols and diastereomeric o-tolyl carbinols. The latter resulted from an unexpected benzyl to o-tolyl rearrangement. The proportion of benzyl versus o-tolyl derivatives depended on the reaction conditions. Benzylmagnesium chloride afforded predominantly o-tolyl carbinols while the application of benzylmagnesium bromide led preferably to the o-tolyl carbinols only when used in excess or at higher temperatures. The structures of the benzyl and o-tolyl derivatives were confirmed unambiguously by NMR spectral data and X-ray crystallographic analysis of their 5-ketone analogues obtained by oxidation of the corresponding mixture of diastereomeric carbinols. A possible mechanism for the Grignard reaction leading to the benzyl→o-tolyl rearrangement is also proposed.

The preparation and photolysis of (E)-1-Aryl-3-methyl-3-phenylbut-1-enes

1983 ◽  
Vol 36 (3) ◽  
pp. 565 ◽  
Author(s):  
JW Blunt ◽  
JM Coxon ◽  
WT Robinson ◽  
HA Schuyt
Keyword(s):  
Reaction Time ◽  
Benzyl Alcohol ◽  
Sulfonic Acid ◽  
Reaction Times ◽  
Grignard Reaction ◽  
Aryl Substituent ◽  
Reaction Conditions ◽  
Careful Choice ◽  
Short Reaction Time ◽  
Toluene Sulfonic Acid

Reaction of 2-methyl-2-phenylpropylmagnesium chloride with benzaldehyde in tetrahydrofuran gave 2,7-dimethyl-2,4,5,7-tetraphenyloctane-4,5-diol as a 1 : 2 mixture of clear transparent crystalline plates (meso) and needles (�), 3-methyl-1,3-diphenylbutan-1-one, benzyl alcohol, 2-methyl-2-phenylpropaneand a low yield of 3-methyl-1,3-diphenylbutan-1-ol. The distinction between the meso and the (+)- diols was unequivocal because the unique space group of the former requires thedimeric molecules to lie about a crystallographic centre of symmetry. The mechanism involved in the formation of the products of the Grignard reaction is examined. By careful choice of reaction conditions a series of I-aryl-3-methyl-3-phenylbutan-1-ols were prepared. Dehydration of the 1-aryl-3-methyl-3-phenylbutan-1-ols with p-toluene sulfonic acid and a short reaction time gives(E)-1-aryl-3-methyl-3-phenylbut-1-enes but longer reaction times afford 3-aryl-1,1-dimethylindanes.Photolysis of the (E)-1-aryl-3-methyl-3-phenylbut-1-enes affords (Z)-1-aryl-3-methyl-3-phenylbut-1-enes and trans-1-aryl-3,3-dimethyl-2-phenylcyclopropanes. Extended photolysis gives 4-aryl-2-methyl-3-phenylbut-1-enes via trans-1-aryl-3,3-dimethyl-2-phenylcyclopropane by rupture of the cyclopropyl bond adjacent to the aryl substituent.

scholarly journals Empowering alcohols as carbonyl surrogates for Grignard-type reactions

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chen-Chen Li ◽  
Haining Wang ◽  
Malcolm M. Sim ◽  
Zihang Qiu ◽  
Zhang-Pei Chen ◽  
...  
Keyword(s):  
Functional Group ◽  
Early Stage ◽  
Grignard Reaction ◽  
Synthetic Chemistry ◽  
Reaction Conditions ◽  
Type Reaction ◽  
Pincer Complex ◽  
Late Stages

AbstractThe Grignard reaction is a fundamental tool for constructing C-C bonds. Although it is widely used in synthetic chemistry, it is normally applied in early stage functionalizations owing to poor functional group tolerance and less availability of carbonyls at late stages of molecular modifications. Herein, we report a Grignard-type reaction with alcohols as carbonyl surrogates by using a ruthenium(II) PNP-pincer complex as catalyst. This transformation proceeds via a carbonyl intermediate generated in situ from the dehydrogenation of alcohols, which is followed by a Grignard-type reaction with a hydrazone carbanion to form a C-C bond. The reaction conditions are mild and can tolerate a broad range of substrates. Moreover, no oxidant is involved during the entire transformation, with only H2 and N2 being generated as byproducts. This reaction opens up a new avenue for Grignard-type reactions by enabling the use of naturally abundant alcohols as starting materials without the need for pre-synthesizing carbonyls.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Dimensionally-Controlled Hydrothermal Tm3+-doped Oxidic Nanocrystals and Their Photoluminescence Properties

2010 ◽  
Vol 1247 ◽  
Author(s):  
Rocío Calderón-Villajos ◽  
Carlos Zaldo ◽  
Concepción Cascales
Keyword(s):  
Single Crystals ◽  
Fluorescence Lifetimes ◽  
Photoluminescence Properties ◽  
Reaction Conditions ◽  
Hydrothermal Processes ◽  
Bulk Single Crystals ◽  
Template Free ◽  
Reaction Media

AbstractControlled reaction conditions in simple, template-free hydrothermal processes yield Tm-Lu2O3 and Tm-GdVO4 nanocrystals with well-defined specific morphologies and sizes. In both oxide families, nanocrystals prepared at pH 7 reaction media exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdVO4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to τrad.

Halogenation of ORMOSIL: A Promising Rout for Tailoring Optical Absorptions

2003 ◽  
Vol 771 ◽  
Author(s):  
Amir Fardad ◽  
Wei Liang ◽  
Yadong Zhang ◽  
Bryson Case ◽  
Shibin Jiang ◽  
...  
Keyword(s):  
Process Parameters ◽  
Sol Gel ◽  
Fiber Amplifiers ◽  
Grignard Reaction ◽  
Coupling Loss ◽  
Beam Splitters ◽  
Silicon Technology ◽  
Sol Gel Process ◽  
Propagation Losses ◽  
Signal Intensities

AbstractFluorinated and photo-imageable precursors are synthesized through a Barbier-Grignard reaction for 1550-nm window. The precursors are used for the sol-gel process of integrated optic components for silica-on-silicon technology. Material compositions and process parameters are optimized to achieve internal absorptions >0.1 dB/cm and propagation losses of about 0.5 dB/cm at 1550 nm. Compact 1×16 Beam splitters are designed and fabricated which exhibit >0.3 dB power uniformity, >0.1 dB PDL and 1.5 dB coupling loss. By hybrid integration of the passive splitters and in-house fiber amplifiers, amplifying splitters are demonstrated at various signal intensities.

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

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