Increased Yields and Simplified Purification with a Second-Generation Cobalt Catalyst for the Oxidative Formation of trans-THF Rings

The synthesis of a second-generation cobalt catalyst for the formation of trans-THF products via the Mukaiyama aerobic oxidative cyclization is reported. Two procedures have been developed with the new water-soluble catalyst that give superior yields and greatly simplify purification compared to the previous catalysts.