Studies towards total synthesis of polyketide natural products and alkaloids

Cascade reactions are powerful synthetic methods, which can be used
to introduce several C-C bonds and chiral centers in only one step.
This thesis deals with synthetic studies toward polyketide type I
and type II natural products as well as alkaloids, which are based
on cascade key steps. In the case of polyketide natural products
A-74528 and divergolides C and D, synthetic key steps inspired by
proposed biomimetic aldol and Michael cascade reactions were
approached. The work towards stephadiamine, a norhasubanan
alkaloid, was focused on the incorporation of homoconjugated
addition/Mannich cascade reaction. In addition, a radical
cyclization step, which is presumably incorporated in the
biogenesis of ansalactam A, was investigated.