Stereoselective arylations using metal phenolates. Complementary synthesis of 5-C-arylxylofuranose derivatives of either L-ido or D-gluco configuration

Cornia, Mara; Casiraghi, Giovanni

doi:10.1016/s0040-4020(01)80115-0

Cited by 32 publications

(6 citation statements)

References 15 publications

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“…The comparative 1 H NMR data of the C5-epimeric pair 7a and 7b turned out to be informative. It is known that for a given C5-epimeric pair, derived from d - gluco -furanose, the J 4,5 in the l - ido isomer ( threo -relationship) is consistently larger than that of the corresponding d - gluco isomer ( erythro -relationship) . The higher value of J 4,5 observed in the diastereomer 7b (9.5 Hz), as compared to 7a (6.9 Hz) indicated the l - ido configuration for 7b and the d - gluco configuration for 7a .…”

Section: Resultsmentioning

confidence: 99%

Intermolecular Michael Addition of Substituted Amines to a Sugar-Derived α,β-Unsaturated Ester: Synthesis of 1-Deoxy-d-gluco- and -l-ido-homonojirimycin, 1-Deoxy-castanospermine and 1-Deoxy-8a-epi-castanospermine

2001

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The synthesis of polyhydroxylated piperidine alkaloids, namely, 1-deoxy-D-gluco-homonojirimycin 3a, 1-deoxy-L-ido-homonojirimycin 3b, and indolizidine alkaloids 1-deoxy-castanospermine 5a and 1-deoxy-8a-epi-castanospermine 5b, has been achieved. The key step involved is the intermolecular Michael addition of benzylamine to alpha,beta-unsaturated ester 1, derived from D-glucose, which afforded diastereomeric mixture of beta-amino esters 6a and 6b with D-gluco- and L-ido- configuration at C5, respectively. Attempts were made to increase and/or alter the diastereoselectivity at the newly generated stereocenter. The high stereoselectivity, in favor of L-ido-isomer 6b, was achieved under kinetically controlled conditions by using lithium N-benzyl amide as a Michael donor. The beta-amino esters 6a and 6b represent common intermediates to target molecules. Thus, LAH reduction of 6a and 6b, individually, gave beta-amino alcohol 7a and 7b. Sequential hydrogenolysis, selective protection of the amino group, followed by hydrolysis of the 1,2-acetonide functionality, and hydrogenation gave 3a and 3b, respectively. On the other hand, the beta-amino ester 6a was converted to gamma-amino ester 13a by Arndt-Eistert synthesis, which on hydrogenolysis and treatment with sodium acetate gave gamma-lactam 14a. The LAH reduction afforded pyrrolidene. The N-protection-hydrolysis-hydrogenation cascade successfully executed, and 1-deoxy-castanospermine 5a was obtained in good yield. The same sequence of reactions was applied to beta-amino ester 6b, which afforded 1-deoxy-8a-epi-castanospermine 5b.

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Section: Resultsmentioning

confidence: 99%

Intermolecular Michael Addition of Substituted Amines to a Sugar-Derived α,β-Unsaturated Ester: Synthesis of 1-Deoxy-d-gluco- and -l-ido-homonojirimycin, 1-Deoxy-castanospermine and 1-Deoxy-8a-epi-castanospermine

2001

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“…The relative stereochemistry at C5 in the epimeric pair 7a and 7b was assigned by comparative 1 H NMR data of 7a and 7b . It is known that for a given C5-epimeric pair, derived from d - gluco furanose, the J 4,5 in the l - ido isomer is consistently larger than that of the corresponding d - gluco isomer . The higher value of J 4,5 in the diastereomer 7a (8.8 Hz) as compared to 7b (7.6 Hz) indicated the l - ido -configuration for 7a and d - gluco -configuration for 7b .…”

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confidence: 88%

“…This assignment was further supported by a comparison of the chemical shifts of the H3 in both the isomers. The chemical shift of H3 is reported to be diagnostic such that in the l - ido -isomer it is significantly upfield as compared to that in the d - gluco . In 7a , the H3 appeared at δ 3.86 upfield as compared to 7b at δ 4.05, further supporting the l - ido - and d - gluco -configuration at C5 to 7a and 7b , respectively.…”

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confidence: 99%

d-Glucose-Derived 1,2,4-Trioxepanes: Synthesis, Conformational Study, and Antimalarial Activity

et al. 2015

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New enantiomerically pure 1,2,4-trioxepanes 10a,b/11a,b were synthesized from D-glucose. Their conformational behavior was studied by low-temperature NMR and substantiated by DFT calculations. On evaluation of in vitro antimalarial activity, the adamantyl derivative 11b showed IC50 values in the low micromolar range, particularly against the W2 chloroquine-resistant Plasmodium falciparum strain (IC50 = 0.15 ± 0.12 μM).

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“…Subsequently, the isomeric mixture of 1a was resolved into pure entities by preparative HPLC (Semi-preparative ODS column; UV: 225 nm; 250 mm × 25 mm; 30% CH 3 CN in potassium buffer; flow rate = 1.0 mL/min). The absolute stereochemistry of major and minor isomer was unambiguously assigned based on the vicinal coupling constants between H-4 and H-5 17,18 and extensive NMR studies. The 1 H NMR spectrum of major isomer (1a) revealed the characteristic H-5 at δ 4.64 as doublet with J 5,4 = 8.9 Hz (L-ido configuration), the same proton in the minor isomer resonated at δ 4.83 as doublet with J 5,4 = 5.9 Hz (D-gluco configuration).…”

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confidence: 99%

Diastereoselective Baylis-Hillmanreaction: Use of Sugar Derived Aldehydes as Chiral Electrophiles

Krishna¹,

Kannan²,

Sharma³

et al. 2003

Synlett

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Stereoselective arylations using metal phenolates. Complementary synthesis of 5-C-arylxylofuranose derivatives of either L-ido or D-gluco configuration

Cited by 32 publications

References 15 publications

Intermolecular Michael Addition of Substituted Amines to a Sugar-Derived α,β-Unsaturated Ester: Synthesis of 1-Deoxy-d-gluco- and -l-ido-homonojirimycin, 1-Deoxy-castanospermine and 1-Deoxy-8a-epi-castanospermine

Intermolecular Michael Addition of Substituted Amines to a Sugar-Derived α,β-Unsaturated Ester: Synthesis of 1-Deoxy-d-gluco- and -l-ido-homonojirimycin, 1-Deoxy-castanospermine and 1-Deoxy-8a-epi-castanospermine

d-Glucose-Derived 1,2,4-Trioxepanes: Synthesis, Conformational Study, and Antimalarial Activity

Diastereoselective Baylis-Hillmanreaction: Use of Sugar Derived Aldehydes as Chiral Electrophiles

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