Regio- and Stereoselective Synthesis of α,β-dehydro-β-amino Esters

Li, Dafeng; Li, Jian; Jia, Xueshun

doi:10.3184/030823408x338684

Cited by 5 publications

(2 citation statements)

References 36 publications

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“…Roy and co-workers 657 have reported synthesis of allyl amines from the acetates of Baylis-Hillman adducts via treatment with amines in the presence of a catalytic amount of ceric ammonium nitrate (CAN) (Scheme 226). Later on, Jia and co-workers 658 transformed the Baylis-Hillman acetates into allyl amines via reaction with alkyl or aryl amines under neat conditions.…”

Section: Applications Of Baylis-hillman Adducts and Their Derivatives...mentioning

confidence: 99%

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

2010

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Section: Applications Of Baylis-hillman Adducts and Their Derivatives...mentioning

confidence: 99%

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

2010

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“…For instance, Helquist reported the tin‐promoted addition of malonate to simple nitriles to give α,β‐dehydro‐β‐amino acid derivatives . Jia and co‐workers reported the synthesis of α,β‐dehydro‐β‐amino esters from Baylis–Hillman acetates with primary amines . Iqbal and co‐workers also independently reported the Pd‐catalyzed reaction of primary amines with Baylis–Hillman acetates for the synthesis of α,β‐dehydro‐β‐amino acid derivatives .…”

Section: Introductionmentioning

confidence: 99%

Regioselective Alkylative Carboxylation of Allenamides with Carbon Dioxide and Dialkylzinc Reagents Catalyzed by an N‐Heterocyclic Carbene–Copper Complex

Gholap

Takimoto

Hou

2016

Chemistry A European J

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The alkylative carboxylation of allenamide catalyzed by an N-heterocyclic carbene (NHC)-copper(I) complex [(IPr)CuCl] with CO2 and dialkylzinc reagents was investigated. The reaction of allenamides with dialkylzinc reagents (1.5 equiv) and CO2 (1 atm.) proceeded smoothly in the presence of a catalytic quantity of [(IPr)CuCl] to afford (Z)-α,β-dehydro-β-amino acid esters in good yields. The reaction is regioselective, with the alkyl group introduced onto the less hindered γ-carbon, and the carboxyl group introduced onto the β-carbon atom of the allenamides. The first step of the reaction was alkylative zincation of the allenamides to give an alkenylzinc intermediate followed by nucleophilic addition to CO2 . A variety of cyclic and acyclic allenamides were found to be applicable to this transformation. Dialkylzinc reagents bearing β-hydrogen atoms, such as Et2 Zn or Bu2 Zn, also gave the corresponding alkylative carboxylation products without β-hydride elimination. The present methodology provides an easy route to alkyl-substituted α,β-dehydro-β-amino acid ester derivatives under mild reaction conditions with high regio- and stereoselectivtiy.

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Asymmetric α‐Allylation of Glycinate with Switched Chemoselectivity Enabled by Customized Bifunctional Pyridoxal Catalysts

Gao

Song

et al. 2022

Angewandte Chemie

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Owing to the strong nucleophilicity of the NH 2 group, free-NH 2 glycinates react with MBH acetates to usually deliver N-allylated products even in the absence of catalysts. Without protection of the NH 2 group, chiral pyridoxal catalysts bearing an amide side chain at the C3 position of the naphthyl ring switched the chemoselectivity of the glycinates from intrinsic N-allylation to α-C allylation. The reaction formed chiral multisubstituted glutamic acid esters as S N 2'-S N 2' products in good yields with excellent stereoselectivity (up to 86 % yield, > 20 : 1 dr, 97 % ee). As compared to pyridoxal catalysts bearing an amide side arm at the C2 position, the pyridoxals in this study have a bigger catalytic cavity to enable effective activation of larger electrophiles, such as MBH acetates and related intermediates. The reaction is proposed to proceed via a cooperative bifunctional catalysis pathway, which accounts for the high level of diastereo-and enantiocontrol of the pyridoxal catalysts.Organocatalytic allylic substitution of Morita-Baylis-Hillman (MBH) adducts is a very useful synthetic transformation, which is capable to transfer various nucleophiles into optically active compounds bearing multiple functional groups. [1][2][3][4][5] When glycinates, a type of important synthons [6] for constructing non-natural amino acids, serve as the nucleophiles, N-addition products 4 and/or 5 are easily formed due to the high nucleophilicity of NH 2 group (Figure 1a). [7] Protecting of the NH 2 group leads to α-C allylation to give S N 2' products 4-alkylidenyl glutamic acid derivatives 7 or S N 2'-S N 2' products 4-methylene glutamic acid derivatives 7' when in the presence of chiral organo-

show abstract

Regio- and Stereoselective Synthesis of α,β-dehydro-β-amino Esters

Cited by 5 publications

References 36 publications

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

Regioselective Alkylative Carboxylation of Allenamides with Carbon Dioxide and Dialkylzinc Reagents Catalyzed by an N‐Heterocyclic Carbene–Copper Complex

Asymmetric α‐Allylation of Glycinate with Switched Chemoselectivity Enabled by Customized Bifunctional Pyridoxal Catalysts

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