Sugar‐Derived Bifunctional Thiourea Organocatalyzed Asymmetric Michael Addition of Acetylacetone to Nitroolefins

Abstract

A bifunctional chiral thiourea organocatalyst bearing a glycosyl scaffold and a tertiary amino group proved to be an effective organocatalyst for the asymmetric Michael addition of acetylacetone to nitroolefins. The corresponding adducts

Dianhydrohexitols: new tools for organocatalysis. Application in enantioselective Friedel-Crafts alkylation of indoles with nitroalkenes

“…[11][12][13][14] Although carbohydrate are very attractive starting material because of their availability and well defined stereocenters, only few thiourea organocatalysts derived from saccharide were used in asymmetric organocatalytic reactions, mainly for Mannich and aza-Henry reactions. [15][16][17][18] As a part of our ongoing program devoted to asymmetric catalysis, we were interested in the development of new chiral ligands derived from dianhydrohexitols (isomannide, isosorbide and isoidide). Ligands derived from dianhydroglycitols have already been used in organometallic catalysis to perform asymmetric Diels-Alder reactions, [19][20][21][22] nucleophilic addition to aldehyde, [23][24] hydrogen transfer reduction of prochiral ketones [25][26][27][28] and asymmetric hydrogenation of olefins.…”

Asymmetric Conjugate Addition of Acetylacetone to Nitroolefins with Chiral Organocatalysts Derived from Both α‐Amino ­Acids and Carbohydrates

“…The highest enantioselectivity in the asymmetric addition of acetylacetone to aliphatic nitroolefins so far was reported to be 85 % ee 9i. During the course of our study, the group of Zhou reported the application of similar chiral tertiary amine–thiourea organocatalysts derived from trans cyclohexane‐1,2‐diamine and D ‐glucopyranose in the asymmetric conjugate addition of acetylacetone to aromatic nitroolefins 9k. However, these organocatalysts could not catalyze the asymmetric addition of acetylacetone to aliphatic nitroolefins.…”

Enantioselective aminocatalysis: Michael addition of unactivated ketones to nitroolefins catalyzed by D-fructose derived monofunctional primary amine

“…In 2008, Zhou et al, reported the advantage of using bifunctional thiourea organocatalysts derived from α-D-glucopyranose, galactose and lactose for asymmetric Michael addition of acetyl acetone to nitro olefins giving up to >99% yield and up to 96% enantioselectivity. 37 Benaglia et al, 38 used another new class of glucosamine-based bifunctional organocatalysts for nucleophilic Michael addition of acetylacetone to nitro olefins and N -Boc imines of benzaldehyde to achieve up to 93% yield and 83% ee. More recently, Peddinti et al, 39 and Shao et al, 40,41 derived from α-amino acids and carbohydrates for asymmetric Michael addition in solvent-free conditions.…”