A new approach to the asymmetric Mannich reaction catalyzed by chiral N,N'-dioxide-metal complexes.

A new approach to the asymmetric Mannich reaction catalyzed by chiral N,N′-dioxide–metal complexes† †Electronic supplementary information (ESI) available. CCDC 1448521 and 1480808.For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc03902b Click here for additional data file. Click here for additional data file.

Chiral ammonium betaine-catalyzed asymmetric Mannich-type reaction of oxindoles

A highly diastereo- and enantioselective Mannich-type reaction of 3-aryloxindoles with N-Boc aldimines was achieved under the catalysis of axially chiral ammonium betaines. This catalytic method provides a new tool for the construction of consecutive quaternary and tertiary stereogenic carbon centers on biologically intriguing molecular frameworks with high fidelity.

Brønsted acid-catalyzed Mannich reaction through dual activation of aldehydes and N-Boc-imines.

In the presence of a Brønsted acid catalyst, both aldehydes and N-Boc-aminals were converted to enecarbamates and N-Boc-iminium salts as activated nucleophiles and electrophiles, respectively, giving unprecedented Mannich adducts. The asymmetric variant of the present Mannich reaction has also been demonstrated with a chiral phosphoric acid catalyst.

3-Bromooxindoles as nucleophiles in asymmetric organocatalytic Mannich reactions with N-Ts-imines.

A direct asymmetric Mannich reaction of N-unprotected 3-bromooxindoles with N-Ts-imines catalyzed by bifunctional thiourea derived from 2-substituted cinchona alkaloid was developed. Products with vicinal chiral tertiary and brominated quaternary stereogenic centers were achieved in excellent diastereo- and enantioselectivity (up to 99 : 1 dr, 99% ee).

Asymmetric synthesis of syn-propargylamines and unsaturated β-amino acids under Brønsted base catalysis

Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric ...