Aziridine ring-containing chiral ligands as highly efficient catalysts in asymmetric synthesis

Efficient Direct Synthesis of Aziridine‐Containing Chiral Tridentate Ligands by the Iminium‐Mediated Self‐Ring Opening Reaction of Enantiopure Aziridines and Salicylaldehydes

“…[4] Moreover, with the rapid development of asymmetric synthesis and catalysis, aziridines have been utilized as chiral auxiliary agents and chiral ligands, respectively. [5] In recent years, the investigations on aziridine-derived chiral ligands have focused on chiral aziridine-containing alcohols, [6] ethers, [7] phenols, [8] semicarbazides, [9] and sulfoxides [10] (L1). Bis-aziridine ligands L2 have also been synthesized and applied in various asymmetric reactions.…”

N-Trityl-aziridinyl alcohols as highly efficient chiral catalysts in asymmetric additions of organozinc species to aldehydes

“…Among chiral amine alcohols, aziridine alcohols constitute as a very interesting class of compounds when applied as chiral ligands especially in the asymmetric additions of organozinc species to carbonyl compounds. [6][7][8][9][10] In continuation of our current interests in the field of asymmetric synthesis, 11,12 especially in the application of aziridine-based chiral catalysts [13][14][15][16][17][18][19][20][21] and taking into account the fact that aziridines strongly coordinate to organozinc species, [22][23][24] we focused our attention on the synthesis of various N-trityl-aziridinyl alcohols and checked their catalytic activity toward the addition of diethylzinc and phenylethynylzinc to aldehydes. According to previous literature reports, such types of chiral catalysts have been tested in model asymmetric additions of diethylzinc to aldehydes to give the corresponding chiral alcohols in high chemical yield (around 90%) and with high enantiomeric excess values (up to 98%).…”

“…According to previous literature reports, such types of chiral catalysts have been tested in model asymmetric additions of diethylzinc to aldehydes to give the corresponding chiral alcohols in high chemical yield (around 90%) and with high enantiomeric excess values (up to 98%). 25,26 It should be noted that either aziridinyl alcohols containing only one stereogenic center located at the aziridine subunit 16,25,26 or aziridinyl alcohols bearing two stereogenic centers (located at C-aziridine atom and C-OH carbon atom 8 ) were very efficient in the aforementioned reactions. However, studies on the influence of the C-OH stereogenic center on catalyst effectiveness have not been performed.…”

Highly efficient conjugate additions of diethylzinc to enones promoted by chiral aziridine alcohols and aziridine ethers

“…It is worth noting that small-molecule amine ether ligands are scarcely reported in the chemical literature. [13][14][15][16] In continuation of our interests in the field of asymmetric synthesis, [17][18][19][20][21] and taking all of the aforementioned results into account, we decided to extend the scope of the applicability of aziridine alcohols 11 and aziridine ethers 12 using them as chiral catalysts for the conjugate Michael additions of diethylzinc to enones.…”