Organocatalytic Asymmetric Anti-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% ee). This process combines an enantioselective organocatalytic anti-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.