Polymerization of mannosyl tricyclic orthoesters for the synthesis of α(1–6) mannopyranan—the backbone of lipomannan

Controlled ring-opening polymerization of 1,2,6-tricyclic orthoesters of mannose toward size–controlled α-d-mannopyranan

“…The homogeneity of the polymer products was verified by 1 H, 13 C NMR and GPC. Characterization by NMR spectroscopy of the products showed very similar spectra as in a previous report (23). The NMR J coupling constants between the anomeric carbon and the anomeric proton (J C13,H1 ) of the well-controlled polymer products from entries 16 and 17 are 171.3 and 171.1 Hz, respectively ( 13 C-1 H-coupled NMR spectra are shown in the supporting information).…”

“…Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 6/7/15 4:18 PM Furthermore, the monomer treated with TMSOTf provided polymer products with narrow-molecular-weight distributions (23).…”

“…The monomer contains a highly strained tricyclic structure, which is readily susceptible to ring-opening polymerizations upon activation with Lewis acids. Trimethylsilyl trifluoromethanesulfonate (TMSOTf) was introduced as an initiator because it gave the desired polymer products with regio-and stereoselectivity (23).…”

“…Reaction temperature, reaction time, equivalent of catalyst as well as monomer concentration were varied for each set of polymerization conditions. The polymerization conditions were adjusted, based on the optimal polymerization conditions in a previously published report (23). In order to observe and account for all the products resulting from polymerizations, the polymer products were characterized by gel permeation chromatography (GPC), 1 H and 13 C in 1D and 2D NMR spectroscopy, optical rotation and melting point.…”

“…A rapid and efficient synthesis of α(1-6) mannopyranan can be done via ring-opening polymerization, utilizing a tricyclic orthoester building block of mannose as a monomer (23). The chemically defined structure of Ph α(1-6) mannopyranan will facilitate biological studies of LM interaction with host immune systems.…”