Enantioselective alkylation of alanine-derived imines using quaternary ammonium catalysts

Lygo, Barry; Crosby, John; Peterson, Justine A.

doi:10.1016/s0040-4039(99)01836-5

Cited by 132 publications

(59 citation statements)

References 24 publications

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“…Probably, the phase-transfer catalysis (PTC) [2] methodology applied to the asymmetric alkylation [1r] of glycine and alanine Schiff bases is the most simple and easy to scale-up. Thus, the advent in the early 1990 s of the enantioselective alkylation of amino acid imines under PTC conditions catalyzed by quaternized Cinchona alkaloids, [3] pioneered by ODonnell [4] and improved by Corey [5] and Lygo, [6] allowed one to obtain impressive degrees of enantioselection using a very simple procedure. Moreover, dimeric, [7] trimeric [8] and even dendrimeric [9] Cinchona alkaloid-derived catalysts, as well as non-Cinchona-derived species such as spiro ammonium [10] and phosphonium salts, [11] TAD-DOL [12a, b] and other tartaric derivatives, [12c, d] guanidinium salts, [12e] binaphthyl-derived amines [12b,13] and salenmetal complexes [14] have also been used in this kind of asymmetric PTC alkylations.…”

Section: Introductionmentioning

confidence: 99%

Polystyrene‐Anchored Cinchona Ammonium Salts: Easily Recoverable Phase‐Transfer Catalysts for the Asymmetric Synthesis of α‐Amino Acids

2004

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Cinchonidine, epicinchonidine, cinchonine or quinine have been N-anchored to cross-linked polystyrene (Merrifield resin) or grafted polystyrene (SynPhase TM Lanterns) affording polymer-supported chiral ammonium salts which are employed as phasetransfer catalysts in the asymmetric alkylation of N-(diphenylmethylene)glycine esters. These new polymeric catalysts can be easily recovered after the reaction by simple filtration and reused.

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Section: Introductionmentioning

confidence: 99%

Polystyrene‐Anchored Cinchona Ammonium Salts: Easily Recoverable Phase‐Transfer Catalysts for the Asymmetric Synthesis of α‐Amino Acids

2004

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“…39 Moreover, this reagent has been frequently applied in alkylation reactions. [40][41][42][43][44][45][46][47] These subjects encouraged us to use this reagent for N-alkylation of phthalimide and sulfonamides via Michael reaction. Thus, at first, we used K 2 CO 3 to accomplish Michael addition of phthalimide to n-butyl acrylate as a model reaction under microwave conditions in [bmim]Br (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…Potassium carbonate (K 2 CO 3 ) is a cheap, commercially available, reusable and green base which has been used frequently in N-, [39][40][41][42] C-, 43,44 and Oalkylation reactions. [45][46][47] Having the above aspects in mind and also in continuation of our previous studies on aza-Michael reactions, 48,49 green organic synthesis, 39,[48][49][50][51][52][53][54][55][56][57] as well as applications of K 2 CO 3 in N-alkylation reactions, 39 we report here our results on the synthesis of N-alkyl derivatives of phthalimide and sulfonamides via Michael addition of phthalimide and sulfonamides to α,β-unsaturated esters using K 2 CO 3 in [bmim]Br under microwave irradiation (Schemes 1 and 2).…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid-Accelerated Synthesis of Some N-Alkyl Derivatwes of Phthalimide and Sulfonamides

Hasaninejad

Zare

Nezhad

et al. 2008

J. Chil. Chem. Soc.

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“…The pioneering studies of O'Donnell and co-workers in 1989 led to the development of a highly practical enantioselective alkylation of a prochiral-protected glycine derivative using Cinchona alkaloid ammonium salts to produce chiral a-amino acids. [195][196][197][198][199][200] Later, Corey [201][202][203] and Lygo [204][205][206][207] independently greatly improved this catalyst system. [208][209][210] Although many types of chiral phase-transfer catalysts have been developed, Cinchona alkaloid derivatives give more impressive enantioselectivity for a range of reactions than do other catalysts, with few exceptions, [213][214][215][216][217][218][219][220][221][222] such as N-spiro binaphtyl derivatives.…”

Section: Catalytic Asymmetric Epoxidation 3-1 Catalytic Asymmetric Ementioning

confidence: 99%

Enantioselective Total Syntheses of Several Bioactive Natural Products Based on the Development of Practical Asymmetric Catalysis

Ohshima

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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I present herewith enantioselective total syntheses of several bioactive natural products, such as (؊)-strychnine, (؉)-decursin, (؊)-cryptocaryolone diacetate, (؊)-fluoxetine, and aeruginosin 298-A, based on practical asymmetric catalyses (Michael reaction, epoxidation, and phase-transfer reaction) that I developed with coworkers in Prof. Shibasaki's group over the past 5 years. In the first part of this review, I discuss the great improvement of catalyst efficiency in an ALB-catalyzed asymmetric Michael reaction of malonate and application to the pre-manufacturing scale (greater than kilogram scale) and enantioselective total synthesis of (؊)-strychnine with the development of novel domino cyclization. To broaden the substrate generality of the Michael reaction, we developed a highly stable, storable, and reusable La-O-linked-BINOL complex. Further extension of the reaction using b b-keto ester as a Michael donor was achieved with the development of a La-NR-linked-BINOL complex, thereby improving indole alkaloid syntheses. In the second section, I discuss enantioselective total synthesis of (؉)-decursin using catalytic asymmetric epoxidation. To achieve the synthesis, we developed a new La-BINOL-Ph 3 As‫؍‬O (1 : 1 : 1) complex catalyst system, which has much higher reactivity and broader substrate generality than the previously developed catalyst systems. This allowed us to achieve catalytic asymmetric epoxidation of a a,b b-unsaturated carboxylic acid derivatives with high enantioselectivity and broad substrate generality for the first time by changing the lanthanide metal and reaction conditions. Among them, catalytic asymmetric epoxidation of a a,b b-unsaturated morpholinyl amides is quite useful in terms of synthetic utility of the corresponding a a,b b-epoxy morpholinyl amides. Highly catalyst-controlled enantio-or diastereoselective epoxidation of the a a,b b-unsaturated morpholinyl amides, coupled with diastereoselective reduction of b b-hydroxy ketones, enabled the synthesis of all possible stereoisomers of 1,3-polyol arrays with successful enantioselective total synthesis of several 1,3-polyol natural products, such as (؊)-cryptocaryolone diacetate. In addition, the development of a new regioselective epoxide-opening reaction of a a,b b-epoxy amides to the corresponding a a-and b b-hydroxy amides enhanced the usefulness of the present epoxidation and was applied to the enantioselective total synthesis of (؊)-fluoxetine. In the final section, I report the development of a new asymmetric two-center organocatalyst (TaDiAS) and its application to the enantioselective synthesis of aeruginosin 298-A and its analogues. Because of the remarkable structural diversity of TaDiAS, a practical asymmetric phase-transfer reaction with broad substrate generality was achieved. As a result, we succeeded in developing a highly versatile synthetic method for aeruginosin 298-A and its analogues. Inhibitory activity studies of the compounds against the serine protease trypsin provided preliminary information about their str...

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Enantioselective alkylation of alanine-derived imines using quaternary ammonium catalysts

Cited by 132 publications

References 24 publications

Polystyrene‐Anchored Cinchona Ammonium Salts: Easily Recoverable Phase‐Transfer Catalysts for the Asymmetric Synthesis of α‐Amino Acids

Polystyrene‐Anchored Cinchona Ammonium Salts: Easily Recoverable Phase‐Transfer Catalysts for the Asymmetric Synthesis of α‐Amino Acids

Ionic Liquid-Accelerated Synthesis of Some N-Alkyl Derivatwes of Phthalimide and Sulfonamides

Enantioselective Total Syntheses of Several Bioactive Natural Products Based on the Development of Practical Asymmetric Catalysis

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