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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.