Asymmetric Two-Fold Michael Reaction. Synthesis of Optically Active 4-Substituted 1-Decalones from Trimethylsilyl Enol Ether of 1-Acetylcyclohexene

Hagiwara, Hisahiro; Akama, Tsutomu; Okano, Akihiro; Uda, Hisashi

doi:10.1246/cl.1989.2149

Cited by 9 publications

(3 citation statements)

References 4 publications

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“…62 A tandem double Michael Figure 38. sequence provided cyclic products with levels of control from 17 to 73% using a variety of 8-phenylmenthol analogues (Figure 37). 63 An intramolecular alkylation with a Michael acceptor was shown by Stork to afford cyclopentanones with good asymmetric induction using 8-phenylmenthol (Figure 3S). 64 The lack of rigidity in the ester linkage between the substrate and the auxiliary as been addressed through the formation of lactone acetals from 8-phenylmenthone (Figure 39).…”

Section: B Nucleophilic Reactionsmentioning

confidence: 99%

Cyclohexyl-based chiral auxiliaries

Whitesell¹

1992

Chem. Rev.

183

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Section: B Nucleophilic Reactionsmentioning

confidence: 99%

Cyclohexyl-based chiral auxiliaries

Whitesell¹

1992

Chem. Rev.

183

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“…Cinchona alkaloids performed particularly well [31 ± 33], leading to an enantioselectivity in the cycloaddition of pyrones to achiral acrylates of up to 74% [34] [35]. Conversely, a diastereoselectivity of up to 70% was observed for the cycloaddition of achiral Li-and TMS-dienolates to enantiomerically pure 8-phenylmenthyl acrylates [36] [37].…”

mentioning

confidence: 99%

Synthesis and Evaluation as Glycosidase Inhibitors of Isoquinuclidines Mimicking a Distorted β‐Mannopyranoside

Böhm

Lorthiois

Meyyappan

et al. 2003

Helvetica Chimica Acta

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Duilio Arigoni, in dankbarer und freundschaftlicher Verbundenheit, zum 75. herzlich zugeeignet Racemic and enantiomerically pure manno-configured isoquinuclidines were synthesized and tested as glycosidase inhibitors. The racemic key isoquinuclidine intermediate was prepared in high yield by a cycloaddition (tandem Michael addition/aldolisation) of the 3-hydroxy-1-tosyl-pyridone 10 to methyl acrylate, and transformed to the racemic N-benzyl manno-isoquinuclidine 2 and the N-unsubstituted mannoisoquinuclidine 3 (twelve steps; ca. 11% from 10). Catalysis by quinine of the analogous cycloaddition of 10 to (À)-8-phenylmenthyl acrylate provided a single diastereoisomer in high yield, which was transformed to the desired enantiomerically pure d-manno-isoquinuclidines ()-2 and ()-3 (twelve steps; 23% from 10). The enantiomers (À)-2 and (À)-3 were prepared by using a quinidine-promoted cycloaddition of 10 to the enantiomeric ()-8-phenylmenthyl acrylate. The N-benzyl d-manno-isoquinuclidine ()-2 is a selective and slow inhibitor of snail b-mannosidase. Its inhibition strength and type depends on the pH (at pH 4.5: K i 1.0 mm, mixed type, a 1.9; at pH 5.5: K i 0.63 mm, mixed type, a 17). The N-unsubstituted d-manno-isoquinuclidine ()-3 is a poor inhibitor. Its inhibition strength and type also depend on the pH (at pH 4.5: K i

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“…Application of the “second” conjugate addition would allow for an approach to the key intermediate 5 in one step starting from three components ( 2 , 3 , and MVK). Acid-catalyzed tandem conjugate addition has been executed in an intramolecular fashion on two previous occasions, but there have been no literature reports of tandem intermolecular addition. Now we report a very short synthetic approach to the vitamin D building blocks 7 and 8 via the common intermediate 6 .…”

mentioning

confidence: 99%

Total Synthesis of 25-Hydroxy Vitamin D₃Northern Portion, Involving Tandem Conjugate Additions

et al. 1998

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New approaches to 25-hydroxy vitamin D building blocks 7 and 8 have been developed. Tandem acid-catalyzed conjugate addition of ketene acetal 2d or 2c and acceptors 3 and then 11 yielded 5b (76% from 3) or 22 (64%), respectively, with the proper relative configuration on C20, C17, and C13 (steroid numbering, all compounds are racemic). The trans-hydrindan ring junction in 16 and 27 has been secured by chirality transfer in palladium-catalyzed hydrogenolysis of formates 15 and 26. Treatment of 16 with N-bromoacetamide followed by NaOH yielded a mixture of 8β,9β- and 8α,9α-epoxides 18 in a ratio of ca. 2:1, which was tosylated and reduced with lithium aluminum hydride without separation. The required diol 20 and its isomer 21 were obtained. In a complementary approach, 27 was oxidized into 8α,9α-epoxide 29 with a new reagent composed of m-CPBA, KF, and 2,6-di-tert-butyl-4-methylphenol. Opening of the epoxide ring in 29 with thiophenoxide anion followed by oxidation afforded dihydroxy sulfone 31. The latter was reduced via the respective dimesylate, and then the protective benzyloxy group was removed yielding 8.

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Asymmetric Two-Fold Michael Reaction. Synthesis of Optically Active 4-Substituted 1-Decalones from Trimethylsilyl Enol Ether of 1-Acetylcyclohexene

Cited by 9 publications

References 4 publications

Cyclohexyl-based chiral auxiliaries

Cyclohexyl-based chiral auxiliaries

Synthesis and Evaluation as Glycosidase Inhibitors of Isoquinuclidines Mimicking a Distorted β‐Mannopyranoside

Total Synthesis of 25-Hydroxy Vitamin D₃Northern Portion, Involving Tandem Conjugate Additions

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Asymmetric Two-Fold Michael Reaction. Synthesis of Optically Active 4-Substituted 1-Decalones from Trimethylsilyl Enol Ether of 1-Acetylcyclohexene

Cited by 9 publications

References 4 publications

Cyclohexyl-based chiral auxiliaries

Cyclohexyl-based chiral auxiliaries

Synthesis and Evaluation as Glycosidase Inhibitors of Isoquinuclidines Mimicking a Distorted β‐Mannopyranoside

Total Synthesis of 25-Hydroxy Vitamin D3Northern Portion, Involving Tandem Conjugate Additions

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Total Synthesis of 25-Hydroxy Vitamin D₃Northern Portion, Involving Tandem Conjugate Additions