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.