Work

Chiral Spiro‐Scaffolded C(sp 3 ),P‐Chelated Iridacycles: Direct Asymmetric Hydrogenation of β,β‐Disubstituted Acrylate Salts

Year: 2026

Type: article

Abstract: ABSTRACT Rational design of chiral ligands with precisely tailored steric and electronic properties is pivotal to advancing asymmetric transition‐metal catalysis. Despite their promising strong σ‐donating ability, sp 3 ‐hybridized carbanion ligands have long been underexplored owing to the inherent instability of C(sp 3 )‐metalated complexes. In this study, we report a modular design of chiral spiro monophosphine ligands (( R )‐SciPhos) integrating an electronic‐withdrawing group, a quaternary carbon moiety, and a rigid spiro scaffold, which efficiently addresses this long‐standing challenge. This judicious design enables the synthesis of bench‐stable neutral C(sp 3 ),P‐chelated iridium complexes via intramolecular C─H activation. These novel iridacycle catalysts exhibit high efficiency, excellent enantioselectivity, and a broad substrate scope in the asymmetric hydrogenation of challenging β,β‐disubstituted sodium acrylates, achieving up to 99% yield and 97% ee with a turnover number (TON) of 5000. Mechanistic studies reveal an Ir(III)/Ir(V) catalytic cycle involving an olefin dihydride iridium(III) intermediate, wherein the migratory insertion step dictates enantioselectivity via noncovalent interactions. This work establishes a general platform for C(sp 3 )‐metalated complex‐based catalysis, opens new avenues for the development of innovative asymmetric catalytic systems, and unlocks access to previously inaccessible enantioselective transformations.

Source: Angewandte Chemie International Edition

DOI: 10.1002/anie.9164765