LECTURE 7 REDUCTIVE ELIMINATIONSa
... • In the SN2 pathway, adopted for polarized A‐B substrates such as alkyl halides, the metal electron pair of LnM directly attacks the A–B σ* orbital by an in‐line attack at the least electronegative atom (where σ* is largest) formally to give LnM2+ , A−, and B− fragments (ionic model). ...
... • In the SN2 pathway, adopted for polarized A‐B substrates such as alkyl halides, the metal electron pair of LnM directly attacks the A–B σ* orbital by an in‐line attack at the least electronegative atom (where σ* is largest) formally to give LnM2+ , A−, and B− fragments (ionic model). ...
KEY Final Exam Review - Iowa State University
... k=(0.2130)M/s/(0.250M)(0.250M)=3.41M-1s-1 could use any of the five to calculate this. kave=3.408M-1s-1 d. What is the rate when [BF3]=0.100M and [NH3]=0.500M? rate=3.408M-1s1*(0.100M)*(0.500M)=0.170M/s 2a. Write the rate law for a reaction between A, B, and C that is the first order in A, zero orde ...
... k=(0.2130)M/s/(0.250M)(0.250M)=3.41M-1s-1 could use any of the five to calculate this. kave=3.408M-1s-1 d. What is the rate when [BF3]=0.100M and [NH3]=0.500M? rate=3.408M-1s1*(0.100M)*(0.500M)=0.170M/s 2a. Write the rate law for a reaction between A, B, and C that is the first order in A, zero orde ...
Exp`t 73
... Interestingly, distillation of the product mixture gives fractions of varying composition, where the lower boiling product distills later. If all of the products were formed instantaneously, then obviously the lower boiling component would be expected to distill earlier; that it does not implies tha ...
... Interestingly, distillation of the product mixture gives fractions of varying composition, where the lower boiling product distills later. If all of the products were formed instantaneously, then obviously the lower boiling component would be expected to distill earlier; that it does not implies tha ...
Carbonyl The carbonyl function, C=O, exists in a number of organic
... Reactions of RXC=O groups; Acid, ester, acid halide, anhydride, amide The characteristic reaction of this class of carbonyl compounds is the first step of addition of the nucleophile followed by elimination of the X function to give the final product. In acid catalysis the carbonyl is first protonat ...
... Reactions of RXC=O groups; Acid, ester, acid halide, anhydride, amide The characteristic reaction of this class of carbonyl compounds is the first step of addition of the nucleophile followed by elimination of the X function to give the final product. In acid catalysis the carbonyl is first protonat ...
CHEMISTRY 1000
... We could try using an extremely good nucleophile like H3C - . Then what would happen? ...
... We could try using an extremely good nucleophile like H3C - . Then what would happen? ...
Chap20 Grignard reagents
... 1) Grignard reagents are nucleophiles that add to the specific types of electrophiles shown in this handout (ie. that are not generally used for SN 2 reactions on alkyl halides). 2) Alkyl Na, Li, and K reagents (i.e. H 3CC CNa ) react very similarly to Grignard reagents. 3) An R – addition to a carb ...
... 1) Grignard reagents are nucleophiles that add to the specific types of electrophiles shown in this handout (ie. that are not generally used for SN 2 reactions on alkyl halides). 2) Alkyl Na, Li, and K reagents (i.e. H 3CC CNa ) react very similarly to Grignard reagents. 3) An R – addition to a carb ...
Arylboronates and Diarylborinates
... Heating of rhodium borinate 7 in cyclohexane at 80 °C led to β-aryl elimination. The corresponding [(PEt3)3Rh(Mes)] (8) and cyclic boroxin {[OdB(Mes)]3}15 (9) were formed in 87% and 91% yields after 4 h (eq 4). Reactions in the presence of 2 equiv of added PEt3 were much slower, and at higher temper ...
... Heating of rhodium borinate 7 in cyclohexane at 80 °C led to β-aryl elimination. The corresponding [(PEt3)3Rh(Mes)] (8) and cyclic boroxin {[OdB(Mes)]3}15 (9) were formed in 87% and 91% yields after 4 h (eq 4). Reactions in the presence of 2 equiv of added PEt3 were much slower, and at higher temper ...
New catalytic transformations of carboxylic acids
... acids to transition-metal catalysts under formation of acyl-metal species, which can either be reduced to aldehydes, or coupled with nucleophiles. At elevated temperatures, such acylmetal species decarbonylate, so that carboxylic acids become synthetic equivalents for aryl or alkyl halides, e.g., in ...
... acids to transition-metal catalysts under formation of acyl-metal species, which can either be reduced to aldehydes, or coupled with nucleophiles. At elevated temperatures, such acylmetal species decarbonylate, so that carboxylic acids become synthetic equivalents for aryl or alkyl halides, e.g., in ...
Experiment 2. Oxidation of an Alcohol (see Ege`s: pp 515-519)
... Brine is highly ionic, thus expelling non-ionic organic compounds/solvents out of the aqueous layer (i.e., brine). “brine and water-immiscible organic solvents separate better → drier organic layer” • The brine washed organic layer still contains a trace amount of water. In order to further remove w ...
... Brine is highly ionic, thus expelling non-ionic organic compounds/solvents out of the aqueous layer (i.e., brine). “brine and water-immiscible organic solvents separate better → drier organic layer” • The brine washed organic layer still contains a trace amount of water. In order to further remove w ...
Williamson Ether Synthesis
... The intramolecular Williamson synthesis is stereospecific. Since the Williamson synthesis is a SN2 substitution reaction, an inversion of configuration occurs at the carbon bearing the leaving group. The leaving group must be on the opposite side of the molecule from the attacking nucleophile in or ...
... The intramolecular Williamson synthesis is stereospecific. Since the Williamson synthesis is a SN2 substitution reaction, an inversion of configuration occurs at the carbon bearing the leaving group. The leaving group must be on the opposite side of the molecule from the attacking nucleophile in or ...
Two-coordinate group 14 element(ii) hydrides as
... which (e.g. I–V, Scheme 1)8–11 have been reported since the turn of the millennium.12 Of these, the three-coordinate silicon(II) hydride, I, has been shown to hydrosilylate cyclopentene and a series of terminal olens at elevated temperatures (70–120 C) and in the presence of large excesses of the ...
... which (e.g. I–V, Scheme 1)8–11 have been reported since the turn of the millennium.12 Of these, the three-coordinate silicon(II) hydride, I, has been shown to hydrosilylate cyclopentene and a series of terminal olens at elevated temperatures (70–120 C) and in the presence of large excesses of the ...
Metal-catalysed approaches to amide bond formation
... to achieve in a catalytic manner, their derivatives, particularly esters, have been explored as an alternative in catalytic amide forming reactions. In 2003, a simple procedure was published by Ranu and Dutta, using a catalytic amount of indium triiodide and an excess of the amine.9 The elimination ...
... to achieve in a catalytic manner, their derivatives, particularly esters, have been explored as an alternative in catalytic amide forming reactions. In 2003, a simple procedure was published by Ranu and Dutta, using a catalytic amount of indium triiodide and an excess of the amine.9 The elimination ...
Document
... a) “Bailar Twist” = Trigonal twist = all three rings move together through a parallel intermediate b) Tetragonal Twists = one ring stays the same and the others move ...
... a) “Bailar Twist” = Trigonal twist = all three rings move together through a parallel intermediate b) Tetragonal Twists = one ring stays the same and the others move ...
Haloalkanes
... except for C—I bond. the C—X bond is polarized: In both substitution and elimination reactions, the carbon-halogen bond breaks heterolytically to give the very stable halide ions Cl- , Br- or IIn nucleophilic substitution, this halogen is replaced by a nucleophile 親核體 which attacks the electropositi ...
... except for C—I bond. the C—X bond is polarized: In both substitution and elimination reactions, the carbon-halogen bond breaks heterolytically to give the very stable halide ions Cl- , Br- or IIn nucleophilic substitution, this halogen is replaced by a nucleophile 親核體 which attacks the electropositi ...
Organic and Inorganic Esters from Alcohols
... As an alternative to the acid-catalyzed conversions of alcohols into haloalkanes, a number of inorganic reagents can convert the alcoholic hydroxyl group into a good leaving group under milder conditions. ...
... As an alternative to the acid-catalyzed conversions of alcohols into haloalkanes, a number of inorganic reagents can convert the alcoholic hydroxyl group into a good leaving group under milder conditions. ...
Summary of Reactions Which Will Appear on Exams
... 42. REACTIONS OF GRIGNARD REAGENTS AND ORGANOLITHIUM COMPOUNDS WITH ESTERS TO FORM TERTIARY ALCOHOLS ...
... 42. REACTIONS OF GRIGNARD REAGENTS AND ORGANOLITHIUM COMPOUNDS WITH ESTERS TO FORM TERTIARY ALCOHOLS ...
Slide 1
... Subsequent reductive slow O +C branched isomer elimination of aldehyde also forms H H OC and coordination of CO Co CO OC regenerates the active OC Co CO OC species A. CO CO ...
... Subsequent reductive slow O +C branched isomer elimination of aldehyde also forms H H OC and coordination of CO Co CO OC regenerates the active OC Co CO OC species A. CO CO ...
Document
... • We Know 2° Carbocations More Stable Than 1° • Major Product Formed From More Stable C+ Intermediate • Means TS in 2° Carbocation Pathway Lower in Energy • Lower Energy of Activation • Activation Energies in 1° Carbocation Pathways Much Larger ...
... • We Know 2° Carbocations More Stable Than 1° • Major Product Formed From More Stable C+ Intermediate • Means TS in 2° Carbocation Pathway Lower in Energy • Lower Energy of Activation • Activation Energies in 1° Carbocation Pathways Much Larger ...
Study Guide for Exam 2-‐ Aldehydes and Ketones
... forming an oxaphosphetane intermediate. Thus, the electrophile is not H+ as in the previous examples but the phosphonium center. The intermediate undergoes a reverse 2+2 process to ...
... forming an oxaphosphetane intermediate. Thus, the electrophile is not H+ as in the previous examples but the phosphonium center. The intermediate undergoes a reverse 2+2 process to ...
resonance effects - HCC Learning Web
... carbocations are too hard to form) Will not work with rings containing an amino group substituent or a strongly electron-withdrawing group ...
... carbocations are too hard to form) Will not work with rings containing an amino group substituent or a strongly electron-withdrawing group ...
Abbreviated Chapter 17 Powerpoint
... • The atom attached to the aromatic ring has a positive or partial positive charge. • Electron density is withdrawn inductively along the sigma bond, so the ring has less electron density than benzene, and thus it will be slower to react. ...
... • The atom attached to the aromatic ring has a positive or partial positive charge. • Electron density is withdrawn inductively along the sigma bond, so the ring has less electron density than benzene, and thus it will be slower to react. ...
PowerPoint 演示文稿
... Prize in Chemistry (1990). Born in Massachusetts, Corey obtained the Ph.D. at M.I.T. (1951), was on the faculty at the University of Illinois (1951-59) where he became full professor at the early age of 27, and since 1959 he has been professor at Harvard. His research associates (graduate students a ...
... Prize in Chemistry (1990). Born in Massachusetts, Corey obtained the Ph.D. at M.I.T. (1951), was on the faculty at the University of Illinois (1951-59) where he became full professor at the early age of 27, and since 1959 he has been professor at Harvard. His research associates (graduate students a ...
1 5.03, Inorganic Chemistry Prof. Daniel G. Nocera Lecture 15 Apr 11
... NO+, CO, CN–, C2H4 > H– > CH3–, PR3 > SO32– > C6H5–, NO2–, I–, SCN– > Br– > Cl– > py > H2O > OH– > NH3 > F– strong π-acceptors ...
... NO+, CO, CN–, C2H4 > H– > CH3–, PR3 > SO32– > C6H5–, NO2–, I–, SCN– > Br– > Cl– > py > H2O > OH– > NH3 > F– strong π-acceptors ...
Diels-Alder Reaction
... cyclohexene rings, and has become such a mainstay of organic synthesis that its discoverers, Otto Diels and Kurt Alder, were awarded the Nobel Prize in Chemistry in 1950 for their discovery of this reaction. Diels-Alder Reaction (Diene Synthesis). FIRST CITATION: O. Diels and K. Alder, Ann. 460, 98 ...
... cyclohexene rings, and has become such a mainstay of organic synthesis that its discoverers, Otto Diels and Kurt Alder, were awarded the Nobel Prize in Chemistry in 1950 for their discovery of this reaction. Diels-Alder Reaction (Diene Synthesis). FIRST CITATION: O. Diels and K. Alder, Ann. 460, 98 ...
Stille reaction
The Stille reaction, or the Migita-Kosugi-Stille coupling, is a chemical reaction widely used in organic synthesis which involves the coupling of an organotin compound (also known as organostannanes) with a variety of organic electrophiles via palladium-catalyzed coupling reaction.The R1 group attached to the trialkyltin is normally sp2-hybridized, including alkenes, and aryl groups; however, conditions have been devised to incorporate both sp3-hybridized groups, such as allylic and benzylic substituents, and sp-hybridized alkynes. These organostannanes are also stable to both air and moisture, and many of these reagents are either commercially available or can be synthesized from literature precedent. However, these tin reagents tend to be highly toxic. X is typically a halide, such as Cl, Br, I, yet pseudohalides such as triflates and sulfonates and phosphates can also be used.The groundwork for the Stille reaction was laid by Colin Eaborn, Toshihiko Migita, and Masanori Kosugi in 1976 and 1977, who explored numerous palladium catalyzed couplings involving organotin reagents. John Stille and David Milstein developed a much milder and more broadly applicable procedure in 1978. Stille’s work on this area might have earned him a share of the 2010 Nobel Prize, which was awarded to Richard Heck, Ei-ichi Negishi, and Akira Suzuki for their work on the Heck, Negishi, and Suzuki coupling reactions. However, Stille died in the plane crash of United Airlines Flight 232 in 1989.Several reviews have been published on the Stille reaction.