Organocatalytic Asymmetric <i>Anti</i>-Selective Michael Reactions of Aldehydes and the Sequential Reduction/Lactonization/Pauson–Khand Reaction for the Enantioselective Synthesis of Highly Functionalized Hydropentalenes

A new method has been developed for the enantioselective synthesis of highly functionalized hydropentalenes bearing up to four stereogenic centers with high stereoselectivity (up to 99% <i>ee</i>). This process combines an enantioselective organocatalytic <i>anti</i>-selective Michael addition with a highly efficient one-pot reduction/lactonization/Pauson–Khand reaction sequence. The structures and absolute configurations of the products were confirmed by X-ray analysis.