1. Reagents in Organic synthesis
March 27, 2017
Reagents in Organic synthesis
Mr. Anand S Burange,
Institute Of Chemical Technology,
Matunga , Mumbai
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

2. What is a chemical reaction?
March 27, 2017
What is a chemical reaction?
Chemical reaction is an effective interaction between two or more molecules/atoms /ions leading to the formation of new compound(s).
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

3. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Reagents to be covered……
Entry
Reagent 1
NaNH2/NH3 2
1,3-propan-dithiol 3
Methylmethyl thiomethyl sulfoxide 4
OsO4, KMnO4 5
NaIO4 6
LTA 7
m-CPBA, Hydrogen peroxide 8
Ozone 9
LAH/NaBH4 10
DIBAL-H and solvent effect 11
Diethyl oxalate 12
Simmon’s Smith Vs Stabilized sulphur ylid 13
Abnormal Witting 14
NaNO2­/HCl (Semi-pinacolone rearrangement)
Role of anti-pariplanar relationship 15
Organoborane and hyperconjugation 16
Pph3 or P(OEt)3 and organosilane reagent 17
Diazomethane 18
PhSeBr 19
MeLi
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

4. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
NaNH2/NH3
Sodamide can be prepared by adding sodium metal to ammonia.
Sodium metal can easily react with any active proton donor with the release of hydrogen gas.
NaNH2/NH3 obtained can be used for benzyne mechanism while NaNH2/NH3 in ethanol is used
for Birch reduction.
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

5. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

6. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
i. NaNH2/NH3
ii. -CH(CO2Et)2
OH-/340o C
NaNH2/NH3
i. Cl-PO(OEt)2/NaH
ii. NaNH2/NH3 (Via Benzyne)
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

7. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
1,3-propan-dithiol
1,3-propan-dithiol is used to change the polarity of carbonyl carbon of aldehydes in order to make it
nucleophilic by using LDA as a base. This change in polarity is called as umpolung.
Using this concept, we can easily prepare any cyclic ketones like cyclopropanone, cyclobutanone, etc.
Protected form of formaldehyde
Again LDA is used to get
which on deprotection using acid/ Hg2+
yields
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

8. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Predict alkyl halide required with 2 eq. of LDA….
BrCH2CH2CH2CH2CH2Br
BrCH2CH2CH2CH2Br
BrCH2CH2Br
BrCH2CH2CH2Br
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

9. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Methylmethyl thiomethyl sulfoxide
-CHO group can be introduced at a beta position of enone system can be asses by using
methylmethyl thiomethyl sulphoxide
i. LDA
iii. H3O+/Hg2+
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

10. ? Baeyer- Villiger Oxidation and migratory aptitude Per acid
March 27, 2017
Baeyer- Villiger Oxidation and migratory aptitude
Per acid ?
Why electrophilic
Stable carboxylate anion
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

11. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Various per acids used for Baeyer Villiger oxidation and epoxidation reactions
Migratory aptitude in Baeyer-Villiger Oxidation Reaction
H> phenyl > tert-alkyl> sec-alkyl > primary alkyl > methyl
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

12. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

13. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Bartlett has proposed one step mechanism for epoxidation of alkene
using per-acid
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

14. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
OsO4 OR KMnO4 OR OsO4/ NMO
OR K2OsO4 /NMO
m-CPBA
CH2I2/ Zn-Cu (Simmon’s Smith)
I2/ AgOAc (Prevost) OR
m-CPBA followed by hydrolysis
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

15. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Some selectivity aspects during epoxidation reactions…..
Stereoselectivity
50:50 both stereo-isomers are formed
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

16. Lecture at KTHM College, Nashik on 15th September 2012
Cleavage of 1,2-diols
March 27, 2017 Vs
No Cleavage
NaIO4 is selective for only cis-diol
LTA breaks both cis and trans diols
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

17. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Ozonolysis at different conditions…
O3 , CH2Cl2
Zn, Me2S
O3 , CH2Cl2
NaBH4 OR LAH
O3 , CH2Cl2
H2O2
Mechanism involves formation of primary ozonoid which on homolysis gives carbonyl oxide radical.
Carbonyl oxide radical on dimerization gives tetraoxane which on breaking yields corresponding carbonyl.
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

18. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
DIBAL-H and Solvent-Effect
It’s a neutral aluminium hydride containing only one hydride species. It’s a convenient reagent for reducing carboxylic acids to alcohols. It can reduce esters to alcohols and aldehydes selectively. Amides and nitriles also yields aldehydes
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

19. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
In Polar solvent
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

20. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
In non-polar solvent
H2O
Stable at low temperature and recovered at -78oC
H3O+
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

21. Lecture at KTHM College, Nashik on 15th September 2012
NaBH4 Vs LAH
Lecture at KTHM College, Nashik on 15th September 2012

22. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Simmons-Smith Cyclopropane Synthesis
It has been developed by H.E. Simmons and R.D. Smith of the DuPont Company. During this synthesis diiodomethane and zinc-copper couple are stirred together with alkene. The diiodomethane and zinc react together to produce carbene like species called as carbenoid which brings stereospecific addition of CH2 directly to the double bond.
Simplest carbene : Methylene
:CH2
Can be easily prepared by thermolysis
or by irradiating diazomethane gas.
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

23. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

24. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Epoxidation and cyclopropanation of alpha-beta unsaturated enone systems
H2O2/OH-
Me2SOCH2-
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

25. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Unstabilized sulphur ylids are useful to convert carbonyls to respective epoxides
+ Me2S
Application of unstabilized sulphur ylid
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

26. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Diazomethane for ring expansion
Diazomethane is a poisonous gas. It must be handled with great care.
CH2N2
Structure:
Needle like nucleophile
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

27. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
Epoxide is a product of side-reaction occurs during this reaction
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

28. !!ANTI PERIPLANAR RELATIONSHIP!! / Elimination reaction
March 27, 2017
!!ANTI PERIPLANAR RELATIONSHIP!! / Elimination reaction
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

29. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
NaNO2­/HCl (Semi-pinacolone rearrangement)
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

30. ph3P=CH2 OR i. Me3SiCH2MgCl ii. H+ iii. KH or HF
Predict the suitable reagents for the following examples….
CH3-O-CH=Pph3
i.Base ii. PhSeBr
iii. Oxidant (e.g. H2O2)
ph3P=CH2 OR i. Me3SiCH2MgCl ii. H+
iii. KH or HF
Peterson olefinating agent better than P-ylid
BF3/DMSO (solvent)

31. Lecture at KTHM College, Nashik on 15th September 2012
March 27, 2017
i. Base/
ii. H+/heat
Diethyl oxalate
Ph3P: /(EtO)3P:
MeLi(Excess)
Lecture at KTHM College, Nashik on 15th September 2012
NET/SET Guidance Lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

32. Lecture at KTHM College, Nashik on 15th September 2012
Organoborane and hyper-conjugation
From Boron, the alkyl group contributing less hyperconjugation
effect migrates to carbonyl carbon
Lecture at KTHM College, Nashik on 15th September 2012

33. Thank you