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Rishi Sharma

2008CYZ8013

Research Scholar

Progress Report

(I Semester of 2009-10)

I have done literature survey related to my research work entitled Organocatalyst.

Aim:Major aim of our propose research is to develop some new and novel

carbohydrate based organocatalyst for performing enantioselective organic reactions.

Research work:

The required material for our synthesis namely, tri-O-acetyl-D-

glucal was prepared from D-glucose in two steps as per literature procedure. Acetylation

followed by bromination of D-glucose 1 using acetic anhydride in the presence of

catalytic amount of percholric acid followed by the addition of red phosphorous and

bromine afforded tetra-O-acetyl-D-glucopyranosyl bromide 2, which on reductive

elimination using zinc dust in acidic condition afforded tri-O-acetyl-D-glucal 3. Tri-O-

acetyl-D-glucal was converted into glucal 4 using Na2CO3. Benzylation of 4 has been

done by benzyl chloride in presence of sodium hydride. This tri-O-benzyl-D-glucal 5 in

presence of chloramine-T and catalytic amount of iodine gave product 6. We performed

the reduction of diamine 6 (which was synthesized in one-pot from readily available tri-

O-benzyl-D-glucal) with 1.25 equiv. of LiAlH4 under reflux condition. Reduction was

smoothly achieved to get the product. On exposure to Mitsunobu condition, compound

underwent a smooth cyclisation to afford exclusively the 2-aminomethyl

polyhydroxylated pyrrolidine. In order to obtain compound 9, initially the protected

polyhydroxylated pyrrolidine 8 was treated with Na/Hg to deprotect both the tosyl groups

or either one of them. Interestingly, compound 8 underwent a smooth cleavage of cyclic

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tosyl group leading to the formation of compound 8 exclusively in and the secondary

tosyl group remained intact under this condition.

OHOHO

OHOH

OH

OAcOAcO

OAc

D-glucose

OAcOAcO

OAc

OAc

Br

Ac2O/HClO4

Red P + Br23 hrs

CH3COONa/gla. AcOH,

Zn dust,CuSO4.5H2O

0 0C, 3 hrs

OHOHO

OHOBnO

BnO

OBnOBnO

BnO

OBn

NHTsNHTs

OHBnOBnO

OBn

NHTsNHTs NTs

OBn

OBnNHTs

OBn

NH

OBn

OBn

OBn

NHTs

MeOH,Na2CO3

00C

5h

NaH,BnCl2,DMF (RT)Chloramine-T,I2,0

0c,

CH3CN,16h

LAH,THF,680C

Na-Hg, Na2Po4,3hPPh3,DEAD (RT)

1 2

3

5 46

7 89

Research work to be done

Now we will utilize 9 as an organocatalyst to perform a varity enantioselective organic

reaction both in aqueous and non aqueous media.

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Reference:

1. Kumar, V.; Ramesh, N. G. Chem. Commun., 2006, 4952-4954.

2. Seayad, J.; List, B. Org. Biomol.Chem., 2005, 3, 719-724.

3. Nakayama, K.; Maruoka K.J. Am. Chem. Soc.,2008, 130, 17666-17667.

4. Nils, D.; Anders, B.; Hans, A.Adv. Syn. Cat., 2004, 346, 1101-1105.

5. Wei, W.; Jian, W.; Hao, L. Org. Lett., 2004, 6, 2820.