Cobalt-catalyzed enantioselective desymmetrizing reductive cyclization of alkynyl cyclodiketones?

Chemical Science Pub Date: 2023-05-15 DOI: 10.1039/D3SC00119A

Abstract

A highly enantioselective cobalt-catalyzed desymmetrizing reductive cyclization of alkynyl cyclodiketones has been developed. Under mild reaction conditions by employing HBpin as a reducing agent and ferrocene-based PHOX as a chiral ligand, a series of polycyclic tertiary allylic alcohols bearing contiguous quaternary stereocenters are achieved in moderate to excellent yields with excellent enantioselectivities (up to 99%). Broad substrate scope and high functional group compatibility are observed in this reaction. A CoH-catalyzed pathway involving alkyne hydrocobaltation followed by nucleophilic addition to the C[double bond, length as m-dash]O bond is proposed. Synthetic transformations of the product are conducted to demonstrate the practical utilities of this reaction.

Graphical abstract: Cobalt-catalyzed enantioselective desymmetrizing reductive cyclization of alkynyl cyclodiketones
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