Stereocontrolled synthesis of the ABCDE ring moiety of ciguatoxin CTX3C

Kobayashi, Shōji; Takahashi, Yusuke; Komano, Kazuo; Heidary, Hossein; Kawada, Yoshifumi; Oishi, Tohru; Tanaka, Shin; Ogasawara, Yoshihiro; Sasaki, Shin ya; Hirama, Masahiro

doi:10.1016/j.tet.2004.07.010

Cited by 44 publications

(21 citation statements)

References 57 publications

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“…The Cl 3 Ti enolates of N-glycolyloxazolidinones also afford syn-aldols preferentially (Table 17), 102,115,117,119,[137][138][139][140][141][142][143][144][145][146][147][148] yet somewhat less selectively than the (alkyl) 2 B-mediated aldol additions of Table 15 and Table 16. If otherwise an incomplete conversion of the oxazolidinone diminishes the yield, an improved protocol by Crimmins and co-workers, which adds NMP, is a remedy.…”

Section: Syn Thesismentioning

confidence: 99%

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Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Engesser¹,

Brückner²

2019

Synthesis

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This review gives a comprehensive overview of aldol additions of glycolic acid derivatives to achiral aldehydes and acetals affording α,β-dihydroxycarboxylic acids or derivatives thereof. The focus is on simple diastereoselectivity. A selection of related aldol additions is also presented: aldol additions of glycolic acid derivatives to ketones with two different substituents and aldol additions of α-substituted glycolic acid derivatives.1 Introduction1.1 Organization of this Review1.2 Outside the Scope of this Review: Aldol Additions Giving α,β-Dihydroxyaldehydes and α,β-Dihydroxyketones Diastereoselectively1.3 Non-Aldol Routes to Diastereomerically Pure α,β-Dihydroxycarboxylic Acid Derivatives2 Aldol Additions of Glycolic Acid (Derivative) Enolates to Aldehydes2.1 Aldol Additions of Glycolate Enolates (‘Glycolic Acid Dianions’)2.2 Aldol Additions of Glycolic Ester Enolates2.3 Aldol Additions of Glycolic Thioester Enolates2.4 Aldol Additions of Glycolimide Enolates2.5 Aldol Additions of Glycolamide Enolates2.6 Mukaiyama Aldol Additions of Silyl Ketene Acetals of Glycolic Esters and Thioesters2.7 Aldol Additions of Glycoloyl Chlorides via Acyl Ammonium Enolates3 Aldol-Providing Substitutions of Glycolimide Enolates in Acetals4 Additions Related to Aldol Additions of Glycolic Acid Derivative Enolates to Aldehydes4.1 Selected Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives to Ketones with Two Different Substituents4.2 Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives with a Methyl Substituent at C-α (Lactic Acid Derivatives)5 Conclusion

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Section: Syn Thesismentioning

confidence: 99%

“…The oxazolidinone moiety of aldol adducts like those present in Tables 15-18 (Table 19) 119,141,142,147,[160][161][162][163] to the Cl 3 Ti enolates of the N-glycolyloxazolidinones (Table 17), providing syn-aldols with good diastereoselectivities. α-Chiral aldehydes react alike.…”

Section: Review Syn Thesis Scheme 21 Mgcl 2 -Catalyzed Anti-selectivementioning

confidence: 99%

Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Engesser¹,

Brückner²

2019

Synthesis

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“…[48] Initial studies were thus conducted with amide 44 a, which was easily obtained by alkylation of 3 a with the N-bromoacetyl amide prepared from (1R,2S)-1-aminoindan-2-ol. [48,49] Treatment of amide 44 a with LiHMDS (2 equiv) in the presence of HMPA (4 equiv, THF, À78 8C) provided a mixture of three diastereomeric a-hydroxy-b-amino amides 45 a, 46 a, and 47 a in a 79:17:4 ratio (69 % combined yield). [31] HMPA was found to exert a strong influence on the syn diastereoselectivity of the [2,3]Wittig rearrangement and increasing the quantity of this polar additive up to 30 equivalents raised the diastereomeric ratio of 45 a/46 a/47 a to 90:5:5 (83 %; Scheme 16).…”

Section: 2-diastereoselectivity Of the Wittig Rearrangement Of A-almentioning

confidence: 99%

Synthesis of 1,2‐Amino Alcohols by Sigmatropic Rearrangements of 3‐(N‐Tosylamino)allylic Alcohol Derivatives

Barbazanges

Meyer

Cossy

et al. 2011

Chemistry A European J

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Sigmatropic rearrangements of 3-(N-tosylamino)allylic alcohol derivatives, a particular subclass of functionalized enamides, have been investigated. Whereas the presence of the nitrogen atom alters the stereochemical outcome of Ireland-Claisen rearrangements of glycolates derived from such substrates, [2,3]-Wittig rearrangements of α-allyloxy acetamides or propargylic ethers derivatives provide access to a wide variety of functionalized 1,2-amino alcohols usually with high levels of stereocontrol, as well as to heterocyclic compounds. The stereoselectivity issues of these rearrangements (1,2-diastereoselectivity, auxiliary-induced diastereoselection, chirality transfer, and double stereodifferentiation) were thoroughly investigated.

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“…A fully functionalized left wing segment 60 of CTX ( 4 ) was synthesized as shown in Figure 8 53. The stereochemistry of coupling with the AB fragment 9 was completely controlled by using 54 , which possesses a chiral aminoindanol auxiliary,54–56 thus avoiding the base‐mediated epimerization at C11 (Figure 4). After derivatization of resultant 55 to the ABCD ring fragment 56 , installation of the dihydroxybutenyl substituent into the allylic acetate 56 was directly achieved by Ni‐catalyzed coupling57,58 with alkenyl borate 57 to afford the ABCD ring fragment 58 , while the regioselectivity is yet to be controlled.…”

Section: Synthesis Of the Left And Right Wing Segments Of Ctxmentioning

confidence: 99%

Total synthesis of ciguatoxin CTX3C: a venture into the problems of ciguatera seafood poisoning

Hirama

2005

The Chemical Record

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After a twelve-year struggle, the total synthesis of ciguatoxin CTX3C has been achieved. Annually, more than 20,000 people worldwide suffer from ciguatera seafood poisoning. The extremely small amounts of the causative neurotoxin, ciguatoxin, in fish hampered the isolation, structural elucidation, detailed biological study, and preparation of anti-ciguatoxin antibodies for detecting these toxins. The large (3 nanometers long) and complicated molecular structure of ciguatoxins hindered chemists from completing a total synthesis. The chemical synthesis of CTX3C, determination of the absolute configuration, and synthesis-based preparation of the monoclonal antibodies as well as the effect of synthetic CTX3C on voltage-sensitive sodium channels are outlined.

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Stereocontrolled synthesis of the ABCDE ring moiety of ciguatoxin CTX3C

Cited by 44 publications

References 57 publications

Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Synthesis of 1,2‐Amino Alcohols by Sigmatropic Rearrangements of 3‐(N‐Tosylamino)allylic Alcohol Derivatives

Total synthesis of ciguatoxin CTX3C: a venture into the problems of ciguatera seafood poisoning

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