1. Functionalization of α-ISAL:
Protection Groups & Polymers
Thomas Robshaw
Supervisor: Professor Andrew Laws

2. Content
Protection
group
chemistry
Substitution
and migration
Elimination Polymerisation

3. Isosaccharinic Acids
Waste product of the paper production industry

4. The Kraft Process
Pulpwood
Saccharinic
acids (20%)
Crude
cellulose
(40%)
Lignins
(20%)
Phenols
(14%)
Others
(6%)
-OH, heat

5. Chemical Peeling of Cellulose
The Nef-Isbell mechanism
J.U. Nef, Just. Lieb. Ann. Chem., 1910, 376, 1-119.
H.S. Isbell, J. Res. Nat. Bur. Stds., 1944, 32, 45-59.

6. α- and β-ISAL

7. Literature
Monneret research group
J.C. Florent et al., J. Org. Chem., 1987, 52, 1051-1056.
M.C. Trinh et al., J. Chem. Soc., Chem. Commun., 1987, 615-616.
2
6

8. Project Aims
Practicalities
Novelties

9. Hydroxyl Group Protection
9-fluorenylmethoxycarbonyl (Fmoc)
Base-labile protecting group

10. Attempts to Improve Yield
J. Ben-Hattar and J. Jiricny, J. Org. Chem., 1986, 51, 3211-3213.
FmocCl + ISAL ISAL(Fmoc) + HCl
Addition of AgNO3
Bi-phase reaction system

11. Reactions with HBr : Acetic Acid System
K. Bock et al., Acta Chem. Scand., 1987, 41, 13-17.
2
6

12. Acyl Group Migration & Cyclisation
M.I. Tamboli et al., Chem. Eur. J., 2015, 21, 13676-13682.

13. Attempted Elimination with Zn Dust

14. Copolymerisation with Methyl Acrylate
α-MBL
M. Moreno et al., J. Polym. Sci., 2014, 52, 3543-3549.
Renewable
latex

15. Conclusions
 Yield of key transformation improved, but not to
commercially viable levels
 Number of novel lactones synthesized
 Polymerisation represents hitherto unreported route
to functionalization

16. Thanks for Your Attention
Acknowledgements:
Prof Andrew Laws
Mustapha S. Galadima
Michael Almond

17. Mechanism of Fmoc Protection
BAC2 type reaction

18. Proposed Schematic
FmocCl
FmocCl
9-methylene-fluorene
9-methylene-fluorene
9-fluorenemethanol
ISAL
ISAL(6-Fmoc)
ISAL(5-Fmoc)
ISAL(Fmoc)2
H2O
CO2
CO2
CO2
HClHCl
HCl
HCl
HCl
CO2
base [?]
FASTSLOW
Fmoc cleavage [base]
slow uncatalysed
fast catalysed
Fmoc cleavage [base]
START
SIDE REACTION 1 SIDE REACTION 2
DESIRED PRODUCT
[?]

19. Zinc Catalysis
Heteroleptic
Intermediate
Di-organozinc
Intermediate
E. Frankland, Just. Lieb. Ann. Chem., 1847, 17, 2.