Biosynthesis-Inspired Approach to Kujounin A2 Using a Stereoselective Tsuji-Trost Alkylation.

A new biosynthesis was proposed for the kujounins A1 and A2 beginning from ascorbic acid, which in turn inspired a synthetic approach to kujounin A2. The ring system was assembled in two steps using a stereoselective Tsuji-Trost reaction followed by ozonolysis. The chemically labile disulfide was introduced in several more steps. These results will make kujounin and its analogues available for further evaluation.