A short diastereoselective synthesis of the (±)-rishirilide B core structure

A series of diastereoselective reactions are reported to form the core of (±)-rishirilide B. The key reactions include: (1) a regioselective tautomerization and etherification of an asymmetric cyclohexa-1,3-dione, (2) an alkoxide directed 1,2-addition of an organometallic reagent and carbamate cleavage and protonation sets two stereocenters, and (3) a novel RuO4 cleavage of an α-hydroxy vinyl ether provides the α-hydroxy ester.