The invention relates to novel synthesis methods for the preparation of the intermediates, which are suitable for the preparation of statin derivatives, especially to novel synthesis methods of the intermediate of formula VI wherein R.sub.a' and R.sub.c' are each independently of the other hydrogen or a hydroxy-protecting group or together are a bridging hydroxy-protecting group, and R.sub.b is a carboxy-protecting group, which methods are carried out by conversion of the intermediate of formula XVI wherein R.sub.a' and R.sub.c' are each independently of the other hydrogen or a hydroxy-protecting group, R* and R** are each independently of the other hydrogen or an amide-protecting group, and R.sub.b is a carboxy-protecting group; which methods proceed to further new intermediates and methods for their preparation ##STR00001##