This document discusses several reagents used in organic synthesis: 1) Wittig reagent is used to synthesize alkenes from ketones and aldehydes via the Wittig reaction. It is prepared from triphenylphosphine and alkyl halides. 2) Diazopropane is used for cyclopropanation of alkenes and is prepared by oxidation of acetohydrazone. 3) BOP reagent is commonly used for peptide coupling and esterification due to its ability to form reactive hydroxybenzotriazolyl intermediates. It involves generation of a carboxylate anion which attacks the phosphorus center.

1. Wittig reagent
Diazopropane
BOP Reagent
BINUJA SS
FIRST YEAR M.PHARM

2. WITTIG REAGENT
• Triphenyl phosphine alkylidienes
Alternative names
• Triphenylphosphoniumylide
• Alkylidienephosphorane
• reagent for the synthesis of alkene from ketones
and aldehydes.
R1 = H
R2 = -CH3 , C2H5,C4H9

3. FORMS OF WITTIG REAGENT
• described in the phosphorane form or the ylide form:

4. GENERAL PREPARATION OF WITTIG REAGENT
• Ph3P + RCH2X→ [Ph3P+CH2R]X−
Phosphonium salt
• [Ph3P+CH2R]X− + C4H9Li → Ph3P=CHR + LiX +
C4H10 Wittig reagent

6. Example :
• Triphenylphospthinemethylidine OR Methylidine
phosphoranes.
• Prepared by
• (C6H5)3P + CH3Br → [(C6H5)3P+CH3]Br− →
methyl bromide methyl phosphonium salt
(C6H5)3P=CH2 + LiBr + C6H6
Methylidiene phosphoranes

7. GENERAL MECHANISM OF WITTIG REAGENT

9. APPLICATIONS
1. Preparation of Olefins
• Wittig reagent provides a method for the
synthesis of olefins.(Wittig reaction)

12. SYNTHESIS OF INDOLE

13. • MECHANISM

14. Synthesis of natural products
• Synthesis of squalene

15. Synthesis of bisabolene

16. Synthesis of beta- carotene.

17. DIAZOPROPANE
• Diazo refers to a type of organic compound called
diazo compound that has two linked nitrogen atoms
(azo) as a terminal functional group.
• reagent is used for the cyclopropanation of alkenes.

18. Preparation
• 2-diazopropane is most commonly prepared by the oxidation
of Acetohydrazone with Mercury(II) Oxide in the presence of
base.

19. APPLICATIONS
1. Cyclopropanation of Alkenes
• prepare gem-dimethylcyclopropyl derivatives.
• This reagent will readily undergo cycloadditions
with alkenes to provide the
corresponding pyrazolines which can be induced
to lose N2 to provide the desired cyclopropanes.

21. Synthesis of ketone.
tropolone
8,8-dimethyl-6-((propan-2-
yl)oxy)bicyclo octan-7-one

22. Syntheis of aristolone
• It is a sesquiterpenes isolated from both the roots of the
Chinese fairy root and rhizome of Canadian ginger and widely
used in traditional medicine.

23. BENZTRIAZOL-1-YLOXY) TRIS
(DIMETHYLAMINO) PHOSPHONIUM
HEXAFLUORO-PHOSPHATE (BOP)
• commonly used in the synthesis of peptides.

24. • Solubility: insoluble in H2O; soluble THF,
CH2Cl2, MeCN, acetone, DMF, NMP, DMSO.
• HMPA

25. APPLICATIONS
1. Peptide coupling
• Peptide bond formation is a nucleophilic substitution reaction
of an amino group (nucleophile) and a carboxyl group via a
tetrahedral intermediate.
• BOP is a very efficient reagent which allows in situ
formation of hydroxybenzotriazolyl esters.

26. MECHANISM OF COUPLING REACTION
WITH BOP
• A tertiary amine is required to generate the carboxylate anion
of the amino acid, which then attacks the phosphorus atom of
BOP. The resulting intermediate A rearranges to form the
hydroxybenzotriazolyl ester B, which is then attacked by the
amine component to form the amide product D via the
stabilized hydrogen-bonded intermediate C.

28. 2. Esterification
• Treatment of N-protected amino acids with phenol, and BOP
in the appropriate solvent (DCM, MeCN, DMF) affords the
corresponding phenyl esters.

29. 3. Lactam Cyclization.
• Cyclization of b-amino acids to b-lactams is efficiently
effected by treatment with BOP .The present method appears
to be limited to the formation of b-lactams from N-
unsubstituted b-amino acids (R1 = R2 = R3 = R5 = H, R4 = Me)

30. 4.Amidation
Preparations include
• N,O-dimethyl hydroxamates of amino acids and
peptides (precursors of chiral peptidyl aldehydes),
• heterocyclic amide fragments in the synthesis of macrolide and
porphyrin models,
• dansylglycine anhydride as a mixed sulfonic-carboxylic imide by
dehydration-cyclization of dansylglycine.
• selective monoacylation of heterocyclic diamine in carbohydrate
series.

32. REFERENCE
• Advanced organic chemistry reactions,mechanisms by Jerry
march, 4th edition,p.no: 956-962.
• Reactions and reagents by O.P.Agarwal, p.no.840-844
• Organic chemistry by Robert Thornton Morrison, Robert Neilson
Boyd, Saibal Kanthi Bhattacharjee, 7th edition, p:no 331-334
• https://en.wikipedia.org/wiki/Diazo#From_amines
• http://onlinelibrary.wiley.com/diazopropane
• http://www.sciencedirect.com/science/article/pii/S00086215008047
23

33. • http://www.brainyresort.com/en/wittig-reaction-
mechanism/
• https://www.google.co.in/search?dcr=0&q=peptide+bo
nd+characteristics
• https://en.wikipedia.org/wiki/BOP_reagent
• http://www.sciencedirect.com/science/article/pii/S0040
403900772571

34. THANK YOU……..