Traceless stereoinduction for the enantiopure synthesis of substituted-2-cyclopentenones.

The pseudoenantiomeric 4-O-Boc- and 4-OPMP-cyclopent-2-enones, readily available from hydroxymethylenefurane on multigram scale, are demonstrated to be exceptional building blocks for the synthesis of enantiopure 4-alkyl-5-(1'-hydroxyalkyl) substituted 2-cyclopentenones and derivatives thereof. The 4-OR substituent acts as a traceless stereoinducing element, conferring not only 1,2- but also 1,4-stereocontrol with excellent selectivity. The methodology developed here was applied for the rapid synthesis of natural products and biologically active 2-cyclopentenones such as TEI-9826, guaianes, and pseudoguaianolides.