Water enables diastereodivergency in bispidine-based chiral amine-catalyzed asymmetric Mannich reaction of cyclic N-sulfonyl ketimines with ketones

Abstract

Tuning diastereoselectivity is a great challenge in asymmetric catalysis for the inherent stereochemical bias of the substrates. Here, we report a diastereodivergent asymmetric Mannich reaction of cyclic N-sulfonyl ketimines with...

Water-enabling strategies for asymmetric catalysis

“…They produced chiral benzosultams with potential anti -HIV-1 activity in one step (Scheme 26). 48 Water could switch the enforced sense of diastereoselectivity. Without additional water, anti -benzosultams were delivered in excellent yields, dr and ee values.…”

Accessing unnatural α-amino acids with tetrasubstituted stereogenic centersviacatalytic enantioselective reactions of ketimine-type α-iminoesters/α-iminoamides

“…30 In 2022, the same group subsequently reported a diastereodivergent version involving cyclic sulfonyl ketimines 4 , which is based on interactions between similar catalyst 42b and additional water (Scheme 16B). 31 The reaction afforded anti -adducts ( anti - 35a ) in the absence of water, which was controlled by a transition state in the C–C bond-forming step. In contrast, syn - 35a were synthesized by selective hydrolysis of the intermediate iminium salt in the presence of additional water.…”

Synthesis of N,N′-Unsymmetrical 9-Amino-5,7-dimethyl-bispidines

“…Bispidines are widely used as chelating compounds that can bind transition metal ions. − The resulting complexes are considered as promising agents for biolabeling and radioimaging. The catalytic activity of bispidine derivatives, especially their chiral derivatives, has also been studied. − One of the key problems in the synthetic chemistry of bispidines, which hinders the development of their applied potential, is the lack of reliable methods for the synthesis of N , N ′-unsymmetrically substituted bispidines, which would make it possible to obtain a wide range of compounds.…”