A Linear Synthesis of Branched High-Mannose Oligosaccharides from the HIV-1 Viral Surface Envelope Glycoprotein gp120

Described is a linear solution-phase synthesis of the HIV-1 viral surface envelope glycoprotein gp120 high-mannose nonasaccharide pentyl glycoside. Envisioning the automated solid-phase assembly of complex carbohydrates, the synthesis of the nonasaccharide and the related tri- and hexamannosides demonstrates the facile assembly of highly branched structures in a stepwise fashion incorporating monosaccharide building blocks. A differentially protected core trisaccharide was prepared and further elongated in two high-yielding tri-mannosylations to furnish the triantennary structure. The tri-, hexa-, and nonamannoside n-pentyl glycosides obtained via the described synthesis are currently being used for detailed study of the carbohydrate protein interactions responsible for binding of the anti-HIV protein cyanovirin-N to the glycoprotein gp120. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)