BIDIRECTIONAL AND CONVERGENT ROUTES TO OLIGO(TETRAHYDROFURANS)

Oligo(tetrahydrofurans) (oligo-THFs) 8-12 have been synthesised stereo selectively. Multiple Williamson reactions were used as key steps. Whi le oligo-TWFs with an even number of THF rings like the bi-THFs 8 and 9 as well as the tetra-THFs 10 and 11 were obtained by a bidirectional strategy, the penta-THF 12 with an odd number of THF rings was prepar ed by a convergent strategy with a sulfone-aldehyde coupling as connec ting step, The oligo-THF products are important structural features of natural (Annonaceae acetogenins) and non-natural (artificial inn chan nels) products.