A Reductive-Coupling plus Nazarov Cyclization Sequence in the Asymmetric Synthesis of Five-Membered Carbocycles

Palladium-mediated hydrostannylation of alkynoyl compounds is combined with Stille-Scott cross-coupling (reductive-coupling) to give one-pot access to divinyl and aryl vinyl ketones, which undergo Nazarov cyclization to give cyclopentenones upon treatment with acid. This reaction sequence has been studied with a variety of different substitution patterns, including the use of oxazolidinone auxiliaries to achieve torquoselectivity in the Nazarov cyclization. Through a combination of good yields and moderate to good levels of stereochemical induction, this approach affords efficient, convergent, and asymmetric access to a variety of different cyclopentanoid systems.