Asymmetric Organic Catalysis with Modified Cinchona Alkaloids

Tian, Shi‐Kai; Chen, Yonggang; Hang, Jianfeng; Tang, Liang; McDaid, Paul; Deng, Li

doi:10.1021/ar030048s

Cited by 584 publications

(177 citation statements)

References 41 publications

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“…Althoughamultitude of realizations of DKR have been developed, [52][53][54][55][56][57] hardly anyo ft hem were carried out in ac ontinuous-flow manner [58][59][60][61][62][63][64][65][66][67][68] ando nly af ew studies realized the KR spaced apart from racemization, allowing separateo ptimization of the two parts of the DKR process. [65][66][67][68] Twoo ft hese DKRs were batch-mode processes with flow-through recirculation [65,66] and only two other cases were real continuous-flow DKRs.…”

Section: Introductionmentioning

confidence: 99%

A Continuous‐Flow Cascade Reactor System for Subtilisin A‐ Catalyzed Dynamic Kinetic Resolution of N‐tert‐Butyloxycarbonylphenylalanine Ethyl Thioester with Benzylamine

et al. 2016

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Alcalase (Subtilisin A) was immobilized by simple hydrophobic adsorption onto various surface-grafted macroporous silicag els resulting in easy-to-prepare and stable biocatalystse nabling the efficient kinetic resolution (KR) and dynamic kinetic resolution (DKR)o fr acemic N-Boc-phenylalanine ethyl thioester with benzylamine.T he immobilized Alcalaseb iocatalysts, which retained their activity and selectivity when stored at 4 8 8Cf or more than ay ear, were testedi ne nzymatic aminolysis in batch and continuous-flow KRs resulting in (S)-N-Bocphenylalanine benzylamide in high enantiomeric purity. In KR of the racemict hioester by Alcalasecatalyzed aminolysis in ac ontinuous-flow reactor, the productivity (specific reactionr ate, r flow )a nd enantiomeric ratio (E)w ere studied in the 0-100 8 8C range.T he effect of the temperature on base-catalyzed racemization of the non-transformed (R)-thioester in ac ontinuous-flow reactor was also investigated in the 0-150 8 8Cr ange.T he continuous-mode DKR of the racemic thioester in as erialc ascade systemo fsix biocatalyst-filled columns at 50 8 8Cf or KR and five grafteds ilica gel-filled columns at 150 8 8Cf or racemization resulted in the formation of the (S)-benzylamide in 79% conversion, 8.17 g L À1 h À1 volumetric productivity and 98% ee. This is the first example of ad ynamic kinetic resolution of an amino acid derivative in continuous-flow mode using an alternating cascade of packed-bed enzyme reactors and racemization reactors kept at different temperatures.

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Section: Introductionmentioning

confidence: 99%

A Continuous‐Flow Cascade Reactor System for Subtilisin A‐ Catalyzed Dynamic Kinetic Resolution of N‐tert‐Butyloxycarbonylphenylalanine Ethyl Thioester with Benzylamine

et al. 2016

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“…1,27 These catalysts are regarded as bifunctional chiral catalysts, bearing a tertiary amino group and hydrogen bond donors, which are expected to possess dual activation of both the electrophilic and nucleophilic components. 25,28,29 In this study, we explore the ability of a urea-type cinchonine and quinine alkaloid derivatives to catalyse the Mannich reaction between the scarcely used N-Boc protected 3-ketoproline substrate with various N-Boc-imines in an effort to create a new route to unnatural proline based amino acids.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective synthesis towards unnatural proline based amino acids

Makhathini¹,

Das²,

Singh³

et al. 2016

Arkivoc

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A catalytic diastereoselective Mannich reaction promoted by chiral bifunctional urea-type organocatalysts has been developed. Treatment of N-Boc-3-ketoproline with N-Boc-aldimines under mild conditions afforded the corresponding unnatural proline based amino acid derivatives with excellent diastereoselectivities (up to 99:1) and enantioselectivities (up to 97% ee). The relative configuration of the chiral reaction products was deduced by the comparsion of the experimentally observed ECD spectra to that obtained theorectically.

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“…As a result, the direct catalytic enantioselective synthesis of the spirocyclic oxindole structure with two quaternary carbon chiral centers 24,25 remains a daunting challenge. Cinchona alkaloids [26][27][28][29][30][31][32][33][34][35][36][37] and their derivatives ( Figure 2) have proven to be powerful organocatalysts for various organocatalytic [38][39][40][41][42] asymmetric C-C bond formations. Recently, isocyanide has been reported as an efficient nucleophile, [43][44][45][46] as the α-hydrogen atom is sufficiently acidic to be deprotonated by cinchona alkaloids.…”

Section: Introductionmentioning

confidence: 99%

Protecting-group directed stereospecific organocatalytic [3+2] cycloadditions: a facile access to chiral spirocyclic oxindoles

Tan¹,

Zhang²,

Zhong³

2014

Arkivoc

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Dedicated to Professor Pierre Vogel on the occasion of his 70 th birthday Abstract An efficient organocatalytic [3+2] cycloaddition between isocyanides and methyleneindolinones, with simultaneous formation of two quaternary stereocenters, for the rapid construction of dihydrospiro[pyrrolidin-3,3′-oxindole] derivatives with high enantiopurity and structural diversity was developed. Furthermore, different protecting group on the nitrogen atom of methyleneindolenones gave rise to a different major diastereoisomer, suggesting a new avenue of great importance to medicinal chemistry and diversity-oriented synthesis.

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Asymmetric Organic Catalysis with Modified Cinchona Alkaloids

Cited by 584 publications

References 41 publications

A Continuous‐Flow Cascade Reactor System for Subtilisin A‐ Catalyzed Dynamic Kinetic Resolution of N‐tert‐Butyloxycarbonylphenylalanine Ethyl Thioester with Benzylamine

A Continuous‐Flow Cascade Reactor System for Subtilisin A‐ Catalyzed Dynamic Kinetic Resolution of N‐tert‐Butyloxycarbonylphenylalanine Ethyl Thioester with Benzylamine

Stereoselective synthesis towards unnatural proline based amino acids

Protecting-group directed stereospecific organocatalytic [3+2] cycloadditions: a facile access to chiral spirocyclic oxindoles

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