Diastereo- and Enantioselective Construction of Spirocycles by Nickel-Catalyzed Cascade Borrowing Hydrogen Cyclization.

Spirocycles play an important role in drug discovery and development owing to their inherent three-dimensionality and structural novelty. Despite the recent significant progress, the straightforward catalytic asymmetric assembly of spirocyclic scaffolds with multiple stereocenters from readily available starting materials remains a formidable challenge. Herein, we develop an unprecedented nickel-catalyzed one-pot synthesis of enantioenriched spiroindanones from easily available 1,6-enynes and o-formylarylboronic acids. The reaction proceeds smoothly under redox-neutral conditions, without the need for an additional hydrogen donor, and features a broad substrate scope and excellent regio-, enantio-, and diastereoselectivity.