Bae HY.
Höfler D.
Kaib PS. J.
Kasaplar P.
De CK.
Döhring A.
Lee S.
Kaupmees K.
Leito I.
List B.
* Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany and University
of Tartu, Estonia
Approaching Sub-ppm-Level Asymmetric Organocatalysis of a Highly Challenging and Scalable
Carbon–Carbon Bond Forming Reaction.
Nat. Chem. 2018;
10: 888-894
Key words
Lewis acid organocatalysis - Mukaiyama aldol reaction - ketones - silyl ketene acetals
- C–C bond formation - asymmetric catalysis
Significance
List and co-workers report the use of chiral organic Lewis acids at ppm- and sub-ppm
levels as catalysts for the challenging asymmetric Mukaiyama aldol reaction of ketones
with silyl ketene acetals. The corresponding products were obtained in excellent yields
and enantioselectivities, even on a decagram scale. The extremely low catalyst loading
is unprecedented in catalytic asymmetric C–C bond-forming reactions.
Comment
Aldehydes are commonly used as electrophiles in the catalytic asymmetric Mukaiyama
aldol reaction, whereas ketones have remained a challenge as substrates for this transformation.
The presented work shows the excellent performance of silylated chiral imidodiphosphorimidates
(Angew. Chem. Int. Ed. 2016, 55, 13200) as powerful Lewis acid catalysts in the aforementioned reaction of both aryl-
and alkyl-substituted ketones.
