Chiral primary β‐amino alcohols, constuting adjacently positioned Brønsted base and Brønsted acid sites, are emerging as very valuable bifunctional organocatalysts in a wide array of asymmetric organic transformations. Primary β‐amino alcohols represent inexpensive alternatives to other primary amino organocatalysts such as chiral diamines and cinchona‐alkaloid‐derived primary amines, being easy to synthesize and air‐stable and offering the potential for introduction of different functional groups and also for alteration of steric sites. Here we reveal the catalytic use of simple primary β‐amino alcohols and their derivatives as organocatalysts in Diels–Alder cycloaddition, aldol condensation, Michael addition, 1,3‐dipolar cycloaddition, the Morita–Baylis–Hillman reaction, cascade cyclization, allylation of isatins, Friedel–Crafts alkylation and epoxidation of olefins.

No abstract

Enantioselective crossed aldol reactions of isatin derivatives and acetaldehyde have been developed with a series of simple diamino alcohol catalysts to afford 3‐substituted 3‐hydroxyindolin‐2‐ones in high chemical yields (up to 95 %) and optical purities (up to 92 % ee). The synthetic potential of the present protocol has been demonstrated by concise, enantioselective, protecting‐group‐free, and transition metal‐free total syntheses of antitumor and antiviral agents with the tryptanthrin architecture, that is, phaitanthrin B and cephalanthrin A, along with the biologically active indolidine alkaloids chimonamidine and donaxaridine as well as the formal synthesis of CPC‐1. The highly enantioselective outcome of this catalytic crossed aldol reaction was evaluated by calculating the Gibbs free energies of the possible transition states.

The new hybrid-type squaramide-fused amino alcohol containing both a Brønsted basic site and hydrogen-bonding sites in the molecule showed a high catalytic activity as an organocatalyst in the enantioselective domino Michael addition/cyclization reaction of oxoindolines with cyclic 1,3-diketones to afford the chiral spiro-conjugated oxindoles featuring 2-aminopyrans fusing with carbo-heterocyclic ring systems with excellent chemical yields (up to 98%) and enantioselectivities (up to 95% ee). The obtained chiral spiro-conjugated 2-aminopyrans bearing quaternary stereogenic carbon center could be used as synthetic precursors for several natural products that have a broad spectrum of fascinating biological activities.

No abstract

Asymmetric Michael addition of β-keto esters with trans-β-nitroolefins using chiral amino amide organocatalyst was tried and afforded synthetically useful chiral Michael adducts in both excellent chemical yields (up to 99%) and stereoselectivities (up to dr. 99:1, up to 98% ee).

A series of hybrid‐type squaramide‐fused amino alcohol (SFAA) catalysts were synthesized, and their catalytic efficiency in the enantioselective nitro‐aldol reaction of various isatins with nitromethane has been described. This transformation afforded chiral 3‐substituted 3‐hydroxyoxindoles in excellent chemical yields (up to 99 %) with high enantioselectivities (up to 95 % ee). The resulting chiral 3‐hydroxyoxindoles can be further used as synthetic precursors for the synthesis of several natural products that have a broad spectrum of fascinating biological activities.

New optically active 2‐azanorbornane‐based amino alcohol organocatalysts were designed and synthesized, and these catalysts were successfully employed in the asymmetric Michael reaction of β‐keto esters with nitroolefins to obtain the corresponding chiral Michael adducts with both high chemical yields (up to 99 %) and high stereoselectivities (up to dr = 91:9, up to 91 % ee).