Dedication
Dedicated to Professor Paul Knochel on the occasion of his 70th birthday.
Abstract
We report a nickel-catalyzed enantioconvergent C(sp3)–C(sp3) cross-coupling between α-iodogermanes and alkylzinc reagents to access α-chiral
alkylgermanes. This transformation, a strategy previously established for silicon-based
electrophiles, extends to germanium, enabling the enantioselective formation of α-chiral
germanes from simple, unactivated alkyl chains. While yields and enantioselectivities
remain moderate, the reaction outcome was finely tuned through the design and evaluation
of a library of over 30 ligands, including more than a dozen novel scaffolds. Notably,
two distinct NiBr₂∙PyBox complexes allowed for access to products of opposite absolute
configuration, and preformed nickel complexes were required to reach synthetically
useful conversions. These findings highlight the challenges of asymmetric catalysis
with heavier main-group elements and provide a platform for the future design of ligands
tailored to organogermanium chemistry.
Keywords
Asymmetric catalysis - C(sp
3)–C(sp
3) cross-coupling - Enantioconvergence - Germanium - Nickel
