Synthesis and Biological Evaluation of Highly Potent Fungicidal Deoxy-Hygrophorones

Based on naturally occurring hygrophorones, racemic di- and mono-hydroxylated cyclopentenones bearing an aliphatic side chain have been produced in short synthetic sequences starting from furfuryl aldehyde. For the series of dihydroxylated trans-configured derivatives, an Achmatowicz-rearrangement and a Caddick-ring contraction were employed, and for the series of trans-configured mono-hydroxylated derivatives a Piancatelli-rearrangement. All final products showed good to excellent fungicidal activities against the plant pathogens B. cinerea, S. tritici and P. infestans.