Total synthesis of the phytotoxic stagonolides A and B

The chemo-enzymatic and covergent synthesis of stagonolide B and the synthesis of stagonolide A, a phytotoxic 10-membered lactone have been achieved starting from d-ribose with overall yields of 25% and 8.7%, respectively. The synthesis contained simple steps in developing three centers’ key intermediates, namely the enzymatic (Novozyme-435) resolution of a propargylic alcohol followed by macrolactonization and RCM.