合成路线1

The intermediate piperidine carboxylic acid (VIII) was obtained as follows: The acetylene orthoester (X) was submitted sequentially to hydrolysis with acetic acid, silylation with TBS-Cl, reduction with DIBAL and Swern oxidation to give the acetylenic aldehyde (XI), which was condensed with 1-acetylpiperidine-2-carboxylic acid (XII), and the resulting compound was esterified with diazomethane, submitted to a Dess-Martin oxidation yielding a tricarbonyl compound that, without isolation was desilylated with HF yielding the cyclic hemiketal (XIII). This hemiketal was silylated with TES-triflate and submitted to hydrostannylation with tributyl tin hydride and AIBN, and tin - iodine exchange with I2/LiI in pyridine at 130 C to afford the desired (E,E)-divinylene iodide fragment (VIII). The syntheses of the starting fragments (I), (II), (IV), (X) and (XII) has already been reported (see Smith, A.B. et al. Tetrahedron Lett 1994, 35(28): 4907 and Smith, A.B. et al. Tetrahedron Lett 1994, 35(28): 4911).