The asymmetric catalytic addition of linear Grignard reagents to ketones has been a long-standing challenge in organic synthesis. Herein, a novel family of PNP ligands (W-Phos) was designed and applied in copper-catalyzed asymmetric addition of linear Grignard reagents to aryl alkyl ketones, allowing facile access to versatile chiral tertiary alcohols in good to high yields with excellent enantioselectivities (up to 94 % yield, 96 % ee). The process can also be used to synthesize chiral allylic tertiary alcohols from more challenging α,βunsaturated ketones. Notably, the potential utility of this method is demonstrated in the gram-scale synthesis and modification of various densely functionalized medicinally relevant molecules.
Catalytic asymmetric addition of reactive Grignard reagents
to
ketimines poses a considerable challenge. Herein, a PNP-type W-Phos ligand developed recently by our group showed a unique
effect toward this end, paving the way to a Cu(I)-catalyzed asymmetric
alkylation reaction of N-sulfonyl ketimines, delivering
optically active α-tertiary amines in high enantioselectivities.
This catalytic protocol shows an unprecedented substrate scope with
more than 80 examples, not only compatible with benzo five- and six-membered
cyclic N-sulfonyl ketimines but also suitable for
geometrically unstable (E or Z)
acyclic N-sulfonyl ketimines. The application potential
of the protocol is featured by the extensive presence of α-tertiary
amines in natural products and pharmaceutical compounds and also demonstrated
by downstream transformations with maintenance of the enantioselectivity.
The asymmetric catalytic addition of linear Grignard reagents to ketones has been a long-standing challenge in organic synthesis. Herein, a novel family of PNP ligands (W-Phos) was designed and applied in copper-catalyzed asymmetric addition of linear Grignard reagents to aryl alkyl ketones, allowing facile access to versatile chiral tertiary alcohols in good to high yields with excellent enantioselectivities (up to 94 % yield, 96 % ee). The process can also be used to synthesize chiral allylic tertiary alcohols from more challenging α,βunsaturated ketones. Notably, the potential utility of this method is demonstrated in the gram-scale synthesis and modification of various densely functionalized medicinally relevant molecules.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.