A New Class of Chiral Pyrrolidine−Pyridine Conjugate Base Catalysts for Use in Asymmetric Michael Addition Reactions

Abstract

Direct catalytic asymmetric Michael addition reactions of ketones to nitroolefins using newly developed chiral pyrrolidine-pyridine conjugate bases as catalysts are described. The desired 1,4-adducts are obtained in excellent yields with high enantio- and diastereoselectivities.

Metalated Heterocycles in Organic Synthesis: Recent Applications

“…Thus, 2-lithiopyridine, obtained by treatment of 2-bromopyridine with nbutyllithium, has been used in addition reactions to ketones, 91 nitriles, 92 amides 93 and the ring-opening of sulfamates. 94 Other substituted 2-pyridyllithium reagents have been obtained similarly and used recently in addition reactions to aldehydes, 95 Weinreb amides, 96 DMF, 97 and acyl chlorides, as in the reaction of the organolithium 30, prepared from 2-bromopyridine 29 by the typical exchange procedure, with pivaloyl chloride (Scheme 10). 98 The so-obtained ketone 31 is an intermediate in the synthesis of a chiral 2,2'-bipyridine oxide catalyst for enantioselective aldol reactions.…”

Green synthesis and antimicrobial evaluation of N-aryl cyclic imides using silica bound benzyl chloride mediated solid phase synthesis

“…Many compounds of succinamide and glutarimide are mentioned in clinical and preclinical analysis [5][6][7][8][9][10][11][12][13] . The substituted pyrrolidine is one of the structural subunits in natural compounds [14][15] . Several substituted pyrrolidine display important biological properties like anticancer 16 , inhibitors of alpha-glucosidase 17 , antimicrobial 18 and other applications [19][20][21][22][23][24][25] .…”

Asymmetric Conjugate Addition of Ketones to β‐Nitrostyrenes by Means of 1,2‐Amino‐Alcohol‐Derived Prolinamides as Bifunctional Catalysts

“…A related study by Enders showed a strong solvent effect in the reaction since in MeOH the enantioselectivity could be increased to 76% for the major syn diastereomer in the reaction between 3-pentanone and trans-β-nitrostyrene employing a 20 mol% of Lproline as catalyst. [7] Since these preliminary studies, very effective catalytic systems (2-20) [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] have been developed for the asymmetric Michael reaction of ketones with nitroalkenes being the process generally syn-selective (Scheme 1). Best improvements to this reaction have been mostly achieved using pyrrolidine-based catalytic derivatives.…”