Multiple Substitutions

We are interested in developing novel synthetic methodologies to modify cyclodextrins. We have reported the unprecedented per-tritylation of CDs.[1] Due to the superior stability of trityl group towards bases, the per-6-O-tritylation should prove to be a very valuable methody that complements the only few methodologies available for per-6-functionalizations.

We have discovered that (DIBAL-H) reagent can be used to selectively remove 1-2 silyl groups from per-6-O-silylated CD derivatives with high regio- and chemoselectivities.[2-3]

In addition, we have also found that the diisobutylaluminum hydride (DIBAL-H) can be used to remove 3-4 benzyl groups from per-O-benzylated CD derivatives in distinct regioselectivities.[4-5]

References

P. Zhang, A. Wang, L. Cui and C.-C. Ling, Org. Lett., 14, 1612-1615 (2012). G. K. Rawal, S. Rani and C.-C. Ling, Tetrahedron Lett., 50, 4633-4636 (2009). R. Ghosh, P. Zhang, A. Wang, C.-C. Ling, Angew. Chem. Int. Ed., 51, 1548-1552 (2012). R. Ghosh, C. Hennigan and C.-C. Ling, Tetrahedron, 69, 5227-5233 (2013). G. K. Rawal, S. Rani, S. Ward and C.-C. Ling, Org. Biomol. Chem., 8, 171-180 (2010).