Our ongoing research projects include (1) development of photolabile protecting groups (PPGs), (2) application of PPGs in synthesis, light-responsive smart materials, controlled release of biologically important compounds, and light-activated anticancer prodrugs, (3) application of new photochemical bond formation reactions in crosslinking macromolecules, labelling proteins, and tissue engineering, (4) development of new facile glycosylation methods, (5) synthesis of carbohydrate antigens for the development of carbohydrate-based vaccines, and (6) development of clinically relevant saponin-based vaccine adjuvants.
Protecting groups are indispensable tools in organic chemistry. Among various protecting groups, photolabile protecting groups (PPGs) have very valuable and unique features: (1) they can be removed under mild conditions by light without using any chemical reagents; and (2) they are capable of releasing substrates in a spatially and temporally controlled manner. These advantages are attractive to both basic and applied sciences. We have developed a series of structurally simple and mechanistically novel PPGs for protection of various functional groups. These PPGs feature (1) ready access from inexpensive materials, (2) highly efficient, flexible, and diverse PPG installation approaches, (3) high deprotection efficiency (even with sunlight irradiation), (4) simple deprotection reaction conditions (compatible with air and water), (5) remarkable dark stability, (6) tunable photochemical property, and (7) flexible structural adjustment.
We have also been pursuing step economy-oriented carbohydrate synthesis in solution phase for rapid access to oligosaccharides of biochemical and biomedical significance. We developed a new glycosylation method using only allyl glycosides as building blocks. Thus, in a one-pot fashion, an allyl glycoside is isomerized to the corresponding prop-1-enyl glycoside donor and its subsequent activation with NIS/TfOH in the presence of an allyl glycosyl acceptor leads to the formation of a new allyl glycoside. The new protocol could markedly simplify carbohydrate synthesis and improve overall synthetic efficiency in that it avoids laborious anomeric manipulations and intermediate purifications often encountered in conventional methods. This approach paves the way to rapid access to structurally well-defined natural/unnatural homogeneous oligo- and poly-saccharides for glycobiology research and development of carbohydrate-based drugs, vaccines, and diagnostic tools.
Keywords - Organic Chemistry, Photochemistry, Carbohydrate Chemistry, Synthetic Methodology, Photoresponsive Materials, Synthetic Vaccines and Vaccine Adjuvants
