Selective Azetidine and Tetrahydropyridine Formation via Pd-Catalyzed Cyclizations of Allene-Substituted Amines and Amino Acids

Rutjes, Floris P. J. T.; Tjen, Kim C. M. F.; Wolf, Larissa B.; Karstens, Willem F. J.; Schoemaker, Hans E.; Hiemstra, Henk

doi:10.1021/ol990700c

Cited by 76 publications

(30 citation statements)

References 18 publications

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“…PhI). However, with enol triflate as alkylating agent, the exclusive formation of azetidines was [45]. This is also the case when the protecting group was a mesitylenesulfonyl (Scheme 3.21) [46].…”

Section: Formation Of a Càn Bondmentioning

confidence: 97%

Four‐Membered Heterocycles: Structure and Reactivity

Rousseau

Robin

2011

Modern Heterocyclic Chemistry

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Section: Formation Of a Càn Bondmentioning

confidence: 97%

Four‐Membered Heterocycles: Structure and Reactivity

Rousseau

Robin

2011

Modern Heterocyclic Chemistry

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Section: Hirokazu Tsukamoto* and Yoshinori Kondomentioning

confidence: 99%

“…These single-step routes C and D involving carboncarbon bond formation at C4 and concomitant C5-C6-N1 and C3-C2-N1 bond formation, respectively, complement each other. [11] We first developed reaction conditions for the cyclization of the terminal-alkyne-containing amine 9 a [12] with the concomitant introduction of a p-methoxyphenyl group at C4 (Table 1) on the basis of those for the related 6-exo-trig cyclization of a 5-alkynal [10a] (Scheme 2). Upon heating at 50 8C in the presence of a slight excess of p-methoxyphenylboronic acid (8 A), aqueous formaldehyde, [13] and a catalytic amount of [Pd(PPh 3 ) 4 ], 9 a underwent arylative cyclization to afford a single cyclized product 1 aA.…”

mentioning

confidence: 99%

Palladium(0)‐Catalyzed Alkynyl and Allenyl Iminium Ion Cyclizations Leading to 1,4‐Disubstituted 1,2,3,6‐Tetrahydropyridines

Tsukamoto

Kondo

2008

Angew Chem Int Ed

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The biologically important title heterocyclic compounds can be synthesized by two methods based on the cyclization of alkynyl and allenyl iminium ions generated in situ in the presence of organometallic reagents (see scheme). Symmetrical and unsymmetrical tetrahydropyridines with diverse substituents R4 were prepared in a single step under mild conditions. R1=n‐, sec‐, tert‐alkyl; R4=aryl, 1‐alkenyl, alkyl, 1‐alkynyl, B(pinacolato).

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“…; entry 3). Subsequent acidic hydrolysis of compound 7b directly produced enantiomerically enriched natural product (S)-12 [20,21] (Scheme 3, bottom). ( see Table S2 in the SupportingI nformation for details).…”

mentioning

confidence: 99%

Synergistic Cu/Pd‐Catalyzed Asymmetric Allenylic Alkylation of Azomethine Ylides for the Construction of α‐Allene‐Substituted Nonproteinogenic α‐Amino Acids

Liu

Wang

et al. 2019

Chemistry A European J

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An unprecedented asymmetrica llenylic alkylation of readily available imine esters, whichw as enabled by as ynergistic Cu/Pd catalysis, has been developed. This dual catalytic system possesses good substrate compatibility,d elivering ad iversea rray of nonproteinogenic a-allenylic a-mono-or a,a-disubstituted a-aminoa cids (a-AAs) with high yields and generally excellent enantioselectivities.F urthermore, the scalability and practicability of the current synthetic protocol were proven by performing gram-scale reactions and by the first catalytic asymmetric synthesis of naturallyo ccurring (S)-g-allenic a-amino acid, respectively.Opticallya ctive nonproteinogenic a-monosubstituted or a,adisubstituted a-amino acids (a-AAs) are privileged constituents of numerousb iologically active natural compounds and pharmaceutical ingredients. [1] For example, these versatile structure motifs have been frequently found in unique enzyme inhibitors [2] and pharmacologically importantn onnatural peptides and proteinsw ith enhanced functionalities. [3] Alternatively, allene-containing compounds have also attracted considerable attention due to their important chemical and biologicalp roperties in synthetic transformations [4] and drug molecules [5] as well as naturalp roducts. [4c, 5a, 6] In view of these unique features of both nonproteinogenic a-AAs and allene units,d eveloping an efficient approach to access nonproteinogenic a-A As bearing an allenic moiety in ah ighly enantioselectivem anner is of great significancea nd also very desirable.With operationally simplicity and synthetically utility,t he palladium-catalyzed enantioselective allenylic alkylation of racemic 2,3-allenol derivatives involving chiral vinyl-p-allylpalladium intermediate [7] has emerged as one of the commonly used tools to synthesize enantiomerically enriched allenes or allenylic substitution products. Among these elegant methodologies using chiral palladium h 3 -butadienyl species as electrophiles, most of the reported examples focusedo nt he construction of allenes with axial chirality, [8] and the established protocols capable of achieving allene derivatives containingc entral chirality [8g, 9] are stillraretod ate (Scheme 1a). Furthermore, the enantiocontrol of nucleophiles has not been touched yet in all of the known cases,p robably due to the synthetic challenges in the palladium-catalyzed asymmetric allylation reaction, that is, the long distance between the catalytic site of the chiral palladium complexa nd the reaction site in nucleophile reagents. [10] Recently,w eand others have developedanew seto fd ual catalytic systemsf or efficient asymmetrica llylic alkylation reactions [10b, 11,12] of readily available iminee sters, in which ac hiral Cu I complex anda chiral [13] or chiral Pd 0 complex [14] has been combined and successfully used as the synergisticc atalysts, leading to various a-quaternary nonproteinogenic a-AAs [15] Scheme1.Catalytic asymmetric allenylic alkylation of non-prochiral nucleophiles withc hiral Pd complex (previous wor...

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Selective Azetidine and Tetrahydropyridine Formation via Pd-Catalyzed Cyclizations of Allene-Substituted Amines and Amino Acids

Cited by 76 publications

References 18 publications

Four‐Membered Heterocycles: Structure and Reactivity

Four‐Membered Heterocycles: Structure and Reactivity

Palladium(0)‐Catalyzed Alkynyl and Allenyl Iminium Ion Cyclizations Leading to 1,4‐Disubstituted 1,2,3,6‐Tetrahydropyridines

Synergistic Cu/Pd‐Catalyzed Asymmetric Allenylic Alkylation of Azomethine Ylides for the Construction of α‐Allene‐Substituted Nonproteinogenic α‐Amino Acids

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