Tandem aldolization/lactonization/dyotropic rearrangement of α-amino-aldehydes

Reetz, Manfred T.; Schmitz, Alina; Holdgrün, Xenia

doi:10.1016/s0040-4039(01)80583-9

Cited by 43 publications

(27 citation statements)

References 23 publications

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“…Historically, various dyotropic reactions have been developed, among which Lewis acid‐promoted dyotropic rearrangement of β‐lactones is particularly notable for its appealing synthetic potential. First discovered by Mulzer and Brüntrup in 1979, [10] this type of transformations has been investigated intermittently by the Black, [11] Reetz, [12] Cossío, [13] and Romo [14] groups over the past decades. A variety of β‐lactones bearing different substitution patterns have been proven to be amenable for this reaction.…”

Section: Introductionmentioning

confidence: 99%

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Lei

Lai

et al. 2020

Angew Chem Int Ed

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An unprecedented strain‐driven dyotropic rearrangement of α‐methylene‐β‐lactones has been realized, which enables the efficient access of a wide range of α‐methylene‐γ‐butyrolactones displaying remarkable structural diversity. Several appealing features of the reaction, including excellent efficiency, high stereospecificity, predictable chemoselectivity and broad substrate scope, render it a powerful tool for the synthesis of MBL‐containing molecules of either natural or synthetic origin. Both experimental and computational evidences suggest that the new variant of dyotropic rearrangements proceed in a dualistic pattern: while an asynchronous concerted mechanism most likely accounts for the reactions featuring hydrogen migration, a stepwise process involving a phenonium ion intermediate is favored in the cases of aryl migration. The great synthetic potential of the title reaction is exemplified by its application to the efficient construction of several natural products and relevant scaffolds.

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Section: Introductionmentioning

confidence: 99%

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Lei

Lai

et al. 2020

Angew Chem Int Ed

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“…[9] Historically,v arious dyotropic reactions have been developed, among which Lewis acid-promoted dyotropic rearrangement of b-lactones is particularly notable for its appealing synthetic potential. First discovered by Mulzer and Brüntrup in 1979, [10] this type of transformations has been investigated intermittently by the Black, [11] Reetz, [12] Cossío, [13] and Romo [14] groups over the past decades.Avariety of b-lactones bearing different substitution patterns have been proven to be amenable for this reaction. With af ew exceptions,m ost dyotropic rearrangements of b-lactones [*] X. Lei, S. Hu, C. Qi, Prof. Dr.G .W ang, Prof. Dr.Y .T ang School of Pharmaceutical Sciences, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology,T singhua University Beijing 100084 (China) E-Mail:gelinwang@tsinghua.edu.cn yefengtang@tsinghua.edu.cn proceeds through ac oncerted mechanism featuring aw elldefined transition state (TS,S cheme 1a), in which the adjacent C4-O1 and C5-R 1 bonds disposed in an anti-coplanar alignment interchange their positions simultaneously,leading to the ring-expansion products in as tereospecific manner.…”

Section: Introductionmentioning

confidence: 99%

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Lei

Lai

et al. 2020

Angewandte Chemie

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“…The 1-O -unprotected monocarbamate was also prepared by a shorter route, starting from ( S )-methionine (11) via the ( S )-N , N -dibenzylhomoserine lactone (12) (according to Reetz), 6 aminolysis to the N , N -dimethylamide 13 , carbamoylation of the γ -hydroxy group and deaminative reduction 11 of the carbamate 14 by means of lithium triethylborohydride (Scheme 3, Table 1). 12 (a) BnBr (3.0 equiv), K 2 CO 3 , NaOH, H 2 O/MeOH, reflux, 45 min; (b) Me 2 NH (11.2 equiv), EtOH/BnOH, 0°C, 48 h; (c) i. NaH (1.5 equiv), THF, r.t., 3 h; ii.…”

Section: Introductionmentioning

confidence: 99%

“…Scheme 2 Table 1. Differentially Protected Monocarbamates 3,4,6,or 7 and Intermediates 8,9,10,12,13,14,15, For the synthesis of the 3-(dimethylamino)butyl carbamate 16, the N-benzyl groups in carbamate 6f were removed by Pd-catalyzed transfer hydrogenolysis, 13 followed by reductive dimethylation, utilizing sodium cyanoborohydride as reacting agent (Scheme 4, Table 1). 14 The 4-O-methyl-and 4-O-TBDMS-protected 1-Ocarbamates 7a and 7b, respectively, and as well the free 1alkanol 4, are also conveniently prepared from the TBDMS ether 8 (Scheme 5, Table 1).…”

Section: Introductionmentioning

confidence: 99%

Monocarbamates, Derived from (S)-2-(Dibenzylamino)butane-1,4-diol, and the Influence of the Second O-Protecting Group on the Regioselectivity of Deprotonation - Application to the Synthesis of the Boletus Toxin (2S,4S)-γ-Hydroxy-norvaline

Sendzik¹,

Guarnieri²,

Hoppe³

1998

Synthesis

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Differentially protected 1-O -and 4-O -monocarbamates, derived from ( S )-2-(dibenzylamino)butane-1,4 -diol are prepared and investigated with respect to their capability of being deprotonated and forming the corresponding lithium carbanions. In the 1-O -trityl and methyl 4-O -monocarbamates 6a and 6b the pro -S -4-H is removed by sec -butyllithium/(-)-sparteine with high diastereoselectivity. The 1-O -(2-methoxyethyl) 4-O -monocarbamate (23e) undergoes a highly selective, substrate-controlled abstraction of the pro -S -4-H without addition of any diamine. On the other hand, the 4-O -methyl 1-O -monocarbamate 7a reacts with sec -butyllithium in diethyl ether with essentially complete stereoselectivity and forms the bicyclic chelate 33 complex with ( S )-configuration at the lithiated C-1 atom. Trapping by means of iodomethane, CO 2 , and other electrophiles proceed with complete stereoretention. The method is applied for the synthesis of Boletus toxin (2 S ,4 S )-γ -hydroxy-norvaline in the form of the lactone hydrochloride. Further, evidence was found that the 2-(dimethylamino) group in the 1-O -TBDMS 4-O -monocarbamate 16 induces a highly substrate-controlled deprotonation in the (4 S )-position.Several methods have been developed in order to differentiate the two carbonyl groups in ( S )-aspartic acid. 5 Fur- Monocarbamates, Derived from ( S )-2-(Dibenzylamino)butane-1,4-diol, and the Influence of the Second O -Protecting Group on the Regioselectivity of Deprotonation -Application to the Synthesis of the Boletus Toxin (2 S ,4 S )-γ -Hydroxy-norvalinether approaches utilize different ( S )-amino acids with a four-carbon backbone such as ( S )-methionine, 5g, 6 ( S )asparagine 7 or the expensive 8 ( S )-homoserine for starting materials. Scheme 1Downloaded by: University of Illinois at Chicago. Copyrighted material.

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Tandem aldolization/lactonization/dyotropic rearrangement of α-amino-aldehydes

Cited by 43 publications

References 23 publications

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Strain‐Driven Dyotropic Rearrangement: A Unified Ring‐Expansion Approach to α‐Methylene‐γ‐butyrolactones

Monocarbamates, Derived from (S)-2-(Dibenzylamino)butane-1,4-diol, and the Influence of the Second O-Protecting Group on the Regioselectivity of Deprotonation - Application to the Synthesis of the Boletus Toxin (2S,4S)-γ-Hydroxy-norvaline

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