Abstract:
Chapter 1 shows four trials to obtain the corestructure of Cruentaren A. The first expressed stategy deals with a Stille coupling of an aromatic building block with a stannan wich was generated by using a 1,5-dialkyne. A following rearangement of the epoxide synthesized out of the product of the Stille coupling closes the first pathway. In the second strategy an epoxide opening is piked up and the already used 1,5-dialkyne is slightly modified for this purpose. The appropriate aromat is coupled under Sonogashira conditions with the dialkyne and subsequently konverted to an isocumarin. With this system some epoxide opening reactions were tested. The third strategy seizes this idea, however changeing the order of junction of the single building blocks. Pathway four describes the use of an benzylmethylether to mask the benzoic acid. With this aromatic building block two sequenced epoxide opening reactions were carried out. The benzylmethylether system could be cleaved into the corresponding aldehyde. The first chapter shows an additional posibility for the synthesis of macrolactones.
Chapter 2 describes the effort to obtain the corestructure of Maoecrystall V by using a domino Stetter-Claisen kondensation. The herefor necessary building block is generated by the reaction of a cyclohexanone with an appropriate phosphonate, generated from valerolactone, under Wittig conditions.