Towards Sustainable Amino Acid Derived Organocatalysts for Asymmetric syn‐Aldol Reactions

Abstract

The undesirable side‐processes responsible for the fast deactivation of primary amino acid derived organocatalysts in asymmetric aldol reactions are identified. A new ionic‐liquid‐supported (S)‐valine‐/(S)‐α,α‐diphenylserinol‐derived catalyst (9) is designed on the basis of these results and exhibits much better recyclability in asymmetric syn‐aldol reactions between hydroxyacetone and aldehydes. Furthermore, this catalyst appeared to be useful for the stereoselective synthesis of the naturally occurring 1(3H)‐isobenzofuran‐1‐one scaffold through an asymmetric syn‐aldol/lactonization cascade reaction.

Comparison of mesoporous fractal characteristics of silica-supported organocatalysts derived from bipyridine-proline and resultant effects on the catalytic asymmetric aldol performances

“…Since List and Barbas (in 2000) rst introduced proline into the asymmetric aldol reaction, 4,5 proline-based derivatives consisting of two or more functional groups are extremely promising homogeneous catalysts as chiral building blocks and chiral ligands in modern asymmetric catalysis [6][7][8][9] due to their low-cost, low toxicity, and environmental friendliness, as well as easy availability, mild reaction conditions, and high selectivity. 10,11 Given these features, relevant explorations presently involve proline and their derivatives, such as amino acids, [12][13][14] peptides, 8,15,16 and chiral amides, 17 as building blocks or ligands in the catalytic asymmetric reactions. A signicant number of axially-unxed 2,2 0 -bipyridine-based chiral bifunctional organocatalysts were synthesized using enantiopure L-proline as chiral sources.…”

“…Given these features, relevant explorations presently involve proline and their derivatives, such as amino acids, 12–14 peptides, 8,15,16 and chiral amides, 17 as building blocks or ligands in the catalytic asymmetric reactions. A significant number of axially-unfixed 2,2′-bipyridine-based chiral bifunctional organocatalysts were synthesized using enantiopure l -proline as chiral sources.…”

Amino Acylguanidines as Bioinspired Catalysts for the Asymmetric Aldol Reaction

“…In this communication, a novel family of bioinspired organocatalysts is presented [ 10 ] ( Figure 1 C) based on the hydrogen bonding features of the acylguanidinium group and its application in the asymmetric aldol reaction of hydroxyacetone, a typical substrate for class I aldolases and thoroughly studied in bioinspired catalysis and organocatalysis. Selected examples are given in references [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”

New Mesoporous Silica-Supported Organocatalysts Based on (2S)-(1,2,4-Triazol-3-yl)-Proline: Efficient, Reusable, and Heterogeneous Catalysts for the Asymmetric Aldol Reaction

“…In this context, several representative organocatalysts present two or more functional groups that act in cooperative or bifunctional strategies [12][13][14][15][16][17][18]. Several research groups have used natural and unnatural amino acids and peptides [19][20][21][22][23][24][25][26][27][28][29][30][31], chiral ureas and thioureas [32][33][34][35][36][37][38][39][40], and chiral amides [41][42][43][44][45] as building blocks or templates in organocatalyst design. In this context, a significant number of (S)-proline derivatives have been developed while searching for an improvement in the catalytic efficiency and stereoselectivity [46][47][48][49][50][51][52][53].…”