Enantioselective Synthesis of Cyclopentene Carbaldehydes by a Direct Multicatalytic Cascade Sequence: Carbocyclization of Aldehydes with Alkynes

Abstract

A multicatalytic, asymmetric cascade reaction sequence of α,β-unsaturated aldehydes with alkyne-tethered nucleophiles has been developed. Organocatalytic iminium–enamine catalysis combined with Lewis acid alkyne activation gave cyclopentene carbaldehyde products in good yields and excellent stereoselectivities (see scheme). To highlight the potential of the sequence, a key structure for the preparation of a fusicoccane diterpenoid analogue was synthesized. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.