A novel, stereodivergent route to paraconic acids from C 2-symmetric trans- and cis-alk-2-ene-1,4-diols through Ireland-Claisen and/or Johnson orthoester rearrangements is disclosed. This strategy has been applied to the synthesis of (-)-methylenolactocin and (-)-phaseolinic acid from a single chiral diol.
A concise approach to (−)-phaseolinicacid starting from commercially available (S)-oct-1-yn-3-ol is disclosed. The key steps are a ring-closing metathesis reaction to prepare a C2-symmetrical allylic diol and its desymmetrization to a γ-butyrolactone by using an Ireland−Claisen rearrangement. The 2S,3S,4S configuration of the levogyre natural product has been confirmed.