Manganese-Catalyzed Epoxidations of Alkenes in
... phosphate, and ammonium or phosphonium counterions to act as phase transfer agents.52-61 Typically, these are formed in situ, but catalytically active complexes such as (R4N)3{PO4(W(O)(O2)2)4} have been isolated and even characterized crystallographically. 62 Noyori showed that terminal aliphatic al ...
... phosphate, and ammonium or phosphonium counterions to act as phase transfer agents.52-61 Typically, these are formed in situ, but catalytically active complexes such as (R4N)3{PO4(W(O)(O2)2)4} have been isolated and even characterized crystallographically. 62 Noyori showed that terminal aliphatic al ...
Working with Hazardous Chemicals
... hydrochloride with phosgene;16 however, the yield is only 36%, and hydrogen chloride must be introduced to increase the yield to 92%. The present procedure effects this reaction without additional hydrogen chloride and avoids the hazards of handling phosgene. This procedure has been successful in th ...
... hydrochloride with phosgene;16 however, the yield is only 36%, and hydrogen chloride must be introduced to increase the yield to 92%. The present procedure effects this reaction without additional hydrogen chloride and avoids the hazards of handling phosgene. This procedure has been successful in th ...
![T_AllylCF3paperBM[5]](http://s1.studyres.com/store/data/003584459_1-3decab572f7fca68901a941affab18ea-300x300.png)
T_AllylCF3paperBM[5]
... cationic center C4 attacks the double bond of the starting alcohol 1 to form benzyl cation, which reacts intramolecularly with arene fragment to cyclize finally to indane. Two new C-C bond and 4 stereocenters are formed and the reaction is rather stereoselective because only two diastereomers are f ...
... cationic center C4 attacks the double bond of the starting alcohol 1 to form benzyl cation, which reacts intramolecularly with arene fragment to cyclize finally to indane. Two new C-C bond and 4 stereocenters are formed and the reaction is rather stereoselective because only two diastereomers are f ...
9851a doc..9851a chapter .. Page97
... Received (in Cambridge, UK) 29th October 2001 First published as an Advance Article on the web 6th February 2002 ...
... Received (in Cambridge, UK) 29th October 2001 First published as an Advance Article on the web 6th February 2002 ...
stereochemistry of internucleotide bond formation by the h
... stereoselectivity during condensing agents-promoted formation of an internucleotidic bond1,2. The activation of ribonucleoside H-phosphonates of type 1 with pivaloyl chloride yields two diastereomers (A and B, Fig. 1) of mixed anhydrides 2. These isomers have to exist in a rapid equilibrium to regen ...
... stereoselectivity during condensing agents-promoted formation of an internucleotidic bond1,2. The activation of ribonucleoside H-phosphonates of type 1 with pivaloyl chloride yields two diastereomers (A and B, Fig. 1) of mixed anhydrides 2. These isomers have to exist in a rapid equilibrium to regen ...
optical isomerism
... The drug, THALIDOMIDE is a chiral molecule and can exist as two enantiomers. In the 1960’s it was used to treat anxiety and morning sickness in pregnant women. Tragically, many gave birth to children with deformities and missing limbs. It turned out that only one of the enantiomers (the structure on ...
... The drug, THALIDOMIDE is a chiral molecule and can exist as two enantiomers. In the 1960’s it was used to treat anxiety and morning sickness in pregnant women. Tragically, many gave birth to children with deformities and missing limbs. It turned out that only one of the enantiomers (the structure on ...
Chapter 18 Ketones and Aldehydes
... Prepared from triphenylphosphine and an unhindered alkyl halide. Butyllithium then abstracts a hydrogen from the carbon attached to phosphorus. Chapter 18 ...
... Prepared from triphenylphosphine and an unhindered alkyl halide. Butyllithium then abstracts a hydrogen from the carbon attached to phosphorus. Chapter 18 ...
Reactions of Alkenes
... Tertiary carbocations are more stable than secondary. The protonation occurs at the least highly substituted end so that the cation produced is at the most highly substituted end (and therefore more stable). Markovnikov’s Rule: The addition of a proton acid to the double bond of an alkene results i ...
... Tertiary carbocations are more stable than secondary. The protonation occurs at the least highly substituted end so that the cation produced is at the most highly substituted end (and therefore more stable). Markovnikov’s Rule: The addition of a proton acid to the double bond of an alkene results i ...
PDF document
... higher for less hindered substrates, indicating that the rate-determining steps were mainly regulated by steric factors. An electron transfer-type process thus forming cation-radical species 12 as the key intermediates, which were further transformed to products 9, 10 or 11, was postulated as the re ...
... higher for less hindered substrates, indicating that the rate-determining steps were mainly regulated by steric factors. An electron transfer-type process thus forming cation-radical species 12 as the key intermediates, which were further transformed to products 9, 10 or 11, was postulated as the re ...
examination paper - University of Calgary
... B The Rf value is defined as (distance solvent front moves)/(distance solute spot moves). C If two spots have the same Rf value, then they must be the same compound D The analgesics were visualised using ninhydrin. E The structure of aspirin is CO2H O O CH3 ...
... B The Rf value is defined as (distance solvent front moves)/(distance solute spot moves). C If two spots have the same Rf value, then they must be the same compound D The analgesics were visualised using ninhydrin. E The structure of aspirin is CO2H O O CH3 ...
C - Deans Community High School
... Reacting hydrogen with ethene to form ethane would be an example of this type of reaction. ...
... Reacting hydrogen with ethene to form ethane would be an example of this type of reaction. ...
full size
... aldehydes are less volatile (higher boiling) than alkanes or ethers but are more volatile than alcohols or carboxylic acids. They are slightly less soluble in water than the alcohols of similar molecular weight. δ− ¾Simple aldehydes have very O pungent and irritating odors and δ+ C are toxic. Aldehy ...
... aldehydes are less volatile (higher boiling) than alkanes or ethers but are more volatile than alcohols or carboxylic acids. They are slightly less soluble in water than the alcohols of similar molecular weight. δ− ¾Simple aldehydes have very O pungent and irritating odors and δ+ C are toxic. Aldehy ...
Nucleophilic Substitution and b
... Acid Catalyzed Dehydration of an Alcohol, discussed earlier as reverse of hydration Secondary and tertiary alcohols, carbocations Protonation, establishing of good leaving group. Elimination of water to yield carbocation in rate determining step. ...
... Acid Catalyzed Dehydration of an Alcohol, discussed earlier as reverse of hydration Secondary and tertiary alcohols, carbocations Protonation, establishing of good leaving group. Elimination of water to yield carbocation in rate determining step. ...
Homogeneously catalysed hydrogenation of unsaturated fatty acids
... become impossible. It is assumed that a small amount of Cd from the wall of the reactor goes into solution in the experiments without Cd-soap supply, but after some hydrogenations this source of Cd is exhausted. The selectivities of the hydrogenations with 2.5, 5 and 7.5% 5i Cu-soap and without Cd-s ...
... become impossible. It is assumed that a small amount of Cd from the wall of the reactor goes into solution in the experiments without Cd-soap supply, but after some hydrogenations this source of Cd is exhausted. The selectivities of the hydrogenations with 2.5, 5 and 7.5% 5i Cu-soap and without Cd-s ...
Selective Incorporation of Difluoromethylene
... physical, and biological properties. Accordingly, the incorporation of fluorine atom(s) or fluorine-containing functionalities into organic molecules has received considerable attention. For decades, extensive reports and reviews mainly focused on the fluorination and perfluoroalkylation (especially ...
... physical, and biological properties. Accordingly, the incorporation of fluorine atom(s) or fluorine-containing functionalities into organic molecules has received considerable attention. For decades, extensive reports and reviews mainly focused on the fluorination and perfluoroalkylation (especially ...
Nucleophilic Additions to Carbonyl Group
... The mechanistic pathway that a reaction follows determines its reaction type. Looking at reactions by their reaction mechanism allows you to relate seemingly different chemical reactions. This chapter examines one of the three mechanistic pathways of the carbonyl group—the addition reaction. The car ...
... The mechanistic pathway that a reaction follows determines its reaction type. Looking at reactions by their reaction mechanism allows you to relate seemingly different chemical reactions. This chapter examines one of the three mechanistic pathways of the carbonyl group—the addition reaction. The car ...
Grignard Reactions - faculty at Chemeketa
... In the Grignard reagent, the bonding electrons between carbon and magnesium are shifted away from the electropositive Mg to form a strongly polar covalent bond. As a result the charge distribution in the Grignard reagent is such that the organic group (R) is partially negative and the –MgX group is ...
... In the Grignard reagent, the bonding electrons between carbon and magnesium are shifted away from the electropositive Mg to form a strongly polar covalent bond. As a result the charge distribution in the Grignard reagent is such that the organic group (R) is partially negative and the –MgX group is ...
Addition of H 2 O to an Alkene
... • Product of electrophilic addition to an alkene involves rupture of a pi bond and formation of two new sigma bonds in its place. In the following addition, however, only 17% of the expected product is formed. • Rearrangement: A reaction in which the product(s) have a different connectivity of atoms ...
... • Product of electrophilic addition to an alkene involves rupture of a pi bond and formation of two new sigma bonds in its place. In the following addition, however, only 17% of the expected product is formed. • Rearrangement: A reaction in which the product(s) have a different connectivity of atoms ...
Carbonyl Chemistry (12 Lectures) Aldehydes and Ketones
... Step 1: Addition of the nucleophilic alkyl group to the carbonyl carbon, aided by Lewis acid interaction between MgX+ and the carbonyl oxygen. The product of this step is a halomagnesium alkoxide (see previous slide). Step 2. Protonation of the alkoxide oxygen. The product of this step is an alcohol ...
... Step 1: Addition of the nucleophilic alkyl group to the carbonyl carbon, aided by Lewis acid interaction between MgX+ and the carbonyl oxygen. The product of this step is a halomagnesium alkoxide (see previous slide). Step 2. Protonation of the alkoxide oxygen. The product of this step is an alcohol ...
Chpt 23Final7e
... F. In the structures of T—A and C—G base pairing, four nitrogens are circled. Given your knowledge of organic functional group names, which of the following is the most appropriate descriptor for the kind of functional group that these nitrogens are part of? 1. An N-heterocyclic ester. 2. An N-aceta ...
... F. In the structures of T—A and C—G base pairing, four nitrogens are circled. Given your knowledge of organic functional group names, which of the following is the most appropriate descriptor for the kind of functional group that these nitrogens are part of? 1. An N-heterocyclic ester. 2. An N-aceta ...
Palladium-Catalyzed Synthesis and Transformation of Organoboranes
... Application of palladium catalysis offers a mild and selective method for synthesis and transformation of allylic organometallic compounds.1 Many excellent methods have been published for synthesis of allylic boranes, silanes, stannanes and other compounds, which are reactive synthetic intermediates ...
... Application of palladium catalysis offers a mild and selective method for synthesis and transformation of allylic organometallic compounds.1 Many excellent methods have been published for synthesis of allylic boranes, silanes, stannanes and other compounds, which are reactive synthetic intermediates ...
Get PDF - Wiley Online Library
... compounds 7b and 8, we decided to investigate the influence of allylic methyl and phenyl substituents on the formation of six-membered cyclic dehydroamino acids via RCM. This required the synthesis of substituted halides 15 and 16, which can then be used in the alkylation of the protected dehydroala ...
... compounds 7b and 8, we decided to investigate the influence of allylic methyl and phenyl substituents on the formation of six-membered cyclic dehydroamino acids via RCM. This required the synthesis of substituted halides 15 and 16, which can then be used in the alkylation of the protected dehydroala ...
Chem 314 Preorganic Evaluation
... E2 Reactions are emphasized in this section special features: biomolecular kinetics (Rate = kE2[RX][B-], single step concerted reaction, competing reaction is SN2 favored reactivity: 3oRX > 2o RX > 1oRX (none at CH3X, need Cβ-H), 1oRX will produce mainly SN2 product excet for mostly E2 with the ster ...
... E2 Reactions are emphasized in this section special features: biomolecular kinetics (Rate = kE2[RX][B-], single step concerted reaction, competing reaction is SN2 favored reactivity: 3oRX > 2o RX > 1oRX (none at CH3X, need Cβ-H), 1oRX will produce mainly SN2 product excet for mostly E2 with the ster ...
Baylis–Hillman reaction
The Baylis–Hillman reaction is a carbon-carbon bond forming reaction between the α-position of an activated alkene and an aldehyde, or generally a carbon electrophile. Employing a nucleophilic catalyst, such as tertiary amine and phosphine, this reaction provides a densely functionalized product (e.g. functionalized allyl alcohol in the case of aldehyde as the electrophile). This reaction is also known as the Morita–Baylis–Hillman reaction or MBH reaction. It is named for the Japanese chemist Ken-ichi Morita, the British chemist Anthony B. Baylis and the German chemist Melville E. D. Hillman.DABCO is one of the most frequently used tertiary amine catalysts for this reaction. In addition, nucleophilic amines such as DMAP and DBU as well as phosphines have been found to successfully catalyze this reaction.MBH reaction has several advantages as a useful synthetic method: 1) It is an atom-economic coupling of easily prepared starting materials. 2) Reaction of a pro-chiral electrophile generates a chiral center, therefore an asymmetric synthesis is possible. 3) Reaction products usually contain multiple functionalities in a proximity so that a variety of further transformations are possible. 4) It can employ a nucleophilic organo-catalytic system without the use of heavy metal under mild conditions.Several reviews have been written.