Appel Reaction, Baylis–Hillman reaction, Boekelheide reaction, Buchwald–Hartwig Coupling, Chugaev elimination, Core-Chaykovsky reaction, Mitsunobu reaction, Shapiro reaction, Sharpless asymmetric epoxidation, Corey–Bakshi–Shibata (CBS) reduction, Kulinkovich reaction

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ImportantNamereaction
CSIR-NET GATE Chemistry

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1.Appel Reaction
CX4, PPh3
X = Cl, Br, I
 The reaction between triphenylphosphine and tetrahalomethane (CCl4, CBr4)forms a salt known as Appel’s salt.
 Treatment of alcohols with Appel’s salt gives rise to the corresponding halides.
PPh3
+PPh3X, CX3
+
Appel salt
Mechanism

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X-
CX3
-
+PPh3-X
Example CCl4, PPh3
DCM, rt, 16h
S. G. Newman, C. S. Bryan, D. Perez, M. Lautens, Synthesis, 2011, 342-346

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2.Baylis–Hillman reaction
TEA
X= O, NR2
EWG = CO2R, COR, CHO, CN, SO2R, SO3R CONR2, PO(Et)2
 It is a carbon-carbon bond-forming transformation of an electron-poor alkene with a carbon electrophile.
 Electron-poor alkenes include acrylic esters, acrylonitrile's, vinyl ketones, vinyl sulfones, and acrolein’s.
 On the other hand, carbon electrophiles may be aldehydes, α alkoxy carbonyl ketones, aldimines,
and Michael acceptors.
Example

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Mechanism

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3.Boekelheide reaction
TFAA
TFAA = Trifluoroacetic anhydride
 Treatment of 2-methylpyridine N-oxide with trifluoroacetic anhydride gives rise to 2-hydroxymethylpyridine.
Hydrolysis
Mechanism

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4. Buchwald–Hartwig Coupling
Pd(OAc)2, dppf,
Base, Toulene
 Direct Pd-catalyzed C–N and C–O bond formation from aryl halides and amines in the presence of
stoichiometric amount of base.
Pd(0)
Oxidative
addition
Ligand Exchange Reductive
elimination
Mechanism

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5. Chugaev elimination
1. CS2, NaOH
2. MeI
xanthate
Heat
OCS CH3SH
 Alcohol converted to xanthates followed by thermal elimination of xanthates to olefins
Heat
Me-I
Mechanism

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6. Core-Chaykovsky reaction
Coreys ylide
1 2.
1 or 2
X = O, CH2
, NR2, S, CHCOR, CHCO2R, CHCN
 The Core-Chaykovsky reaction entails the reaction of a sulphur ylide, either dimethylsulfoxonium methylide
1 (Corey’s ylide) or dimethyl sulfonium methylide 2 with electrophile such as carbonyl, olefin, imine, or
thiocarbonyl, to offer as the corresponding epoxide, cyclopropane, aziridine, or thiirane.
Mechanism

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7.Mitsunobu reaction
NuH
DEAD, PPh3
 SN2 inversion of an alcohol by a nucleophile using diethyl azodicarboxylate (DEAD) and triphenylphosphine
:PPh3
DEAD
Adduct formation
H-Nu
Alcohol
Activation
Nu-
Mechanism

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8. Prévost trans and Woodward cis-dihydroxylation reaction
I2, AgOAc
H2O, H+
I2, AgO2CPh
Hydrolysis
Woodward Product Prevost Product
I2
SN2
-O2CPh
-O2CPh Hydrolysis
Prevost (trans) hydroxylation mechanism
Woodward cis hydroxylation mechanism
I2
SN2
Hydrolysis
-OAc
:OH2

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9.Shapiro reaction
-
E+
2 nBuLi
 The Shapiro reaction is a variant of the Bamford-Stevens reaction. The former uses bases such as alkyl lithium
and Grignard reagents whereas the latter employs bases such as Na, NaOMe, LiH, NaH, NaNH2, etc.
 Consequently, the Shapiro reaction generally affords the less-substituted olefins as the kinetic products, while
he Bamford-Stevens reaction delivers the more-substituted olefins as the thermodynamic products.
nBu-
nBu- -N2 -
E+
Mechanism

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nBuLi
Less Substituted product
MeONa
More subsitituted product
Shapiro reactionBamford-Stevens reaction

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10. Sharpless asymmetric epoxidation
tBu-O-OH, Ti(OiPr)4
L- (+) -Diethyl tartrate
 Enantioselective epoxidation of allylic alcohols using t-butyl peroxide, titanium tetra-iso-propoxide, and
optically pure diethyl tartrate
tBu-O-OH, Ti(OiPr)4
L- (-) -Diethyl tartrate

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11. Corey–Bakshi–Shibata (CBS) reduction
BH3, THF
 Enantioselective borane reduction of ketones catalysed by chiral oxazaborolidines

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12. Kulinkovich reaction
Ti(iOPr)4
H+
 In the Kulinkovich reaction formation cyclopropanols via reaction of esters with dialkyldialkoxytitanium
reagents, generated in situ from Grignard reagents bearing hydrogen in beta-position and titanium(IV)
alkoxides such as titanium isopropoxide

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