Synthesis of central spiro-bis-THF fragments of symbiospirols A-C

The gold catalysed alkynediol spiroketalization to assemble the central spiro-bis-THF fragments (C22-C33 and C36-C47) of symbiospirols A-C is documented. The adopted chiral pool approach employed commercially available d-glucose and l-malic acid in the synthesis of key building blocks. In addition, two other possible diastereomers have been synthesized in order to establish the relative stereochemistry of the unassigned THF-center of symbiospirols B/C.

Automated summary

This study documents the gold catalysed alkynediol spiroketalization for assembling the central spiro-bis-THF fragments of symbiospirols A-C. The chiral pool approach using commercially available d-glucose and l-malic acid was employed to synthesize key building blocks. Additionally, two other possible diastereomers were synthesized to determine the relative stereochemistry of the unassigned THF-center of symbiospirols B/C.