Convergent and stereoselective method for synthesis of O -linked oxepane ring system by intramolecular radical cyclization

Sasaki, Makoto; Inoue, M.; Noguchi, Tetsuji; Takeichi, Atsuo; Tachibana, Kunihide

doi:10.1016/s0040-4039(98)00338-4

Cited by 60 publications

(20 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In 1999, Sasaki et al disclosed a method for the construction of cyclic polyethers from mixed phenylthio acetals (Scheme 20). [70] Reaction of bicyclic O,S-acetal 118 with nBu 3 SnH in the presence of AIBN proceeded, presumably through radical species 119, to afford tricyclic polyether 120 stereoselectively and in 85 % yield. The observed stereoselectivity was attributed to the preferred transition state 119, which minimizes unfavorable interactions between two axial substituents.…”

Section: Synthetic Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Continuing Saga of the Marine Polyether Biotoxins

2008

View full text Add to dashboard Cite

The unprecedented structure of the marine natural product brevetoxin B was elucidated by the research group of Nakanishi and Clardy in 1981. The ladderlike molecular architecture of this fused polyether molecule, its potent toxicity, and fascinating voltage-sensitive sodium channel based mechanism of action immediately captured the imagination of synthetic chemists. Synthetic endeavors resulted in numerous new methods and strategies for the construction of cyclic ethers, and culminated in several impressive total syntheses of this molecule and some of its equally challenging siblings. Of the marine polyethers, maitotoxin is not only the most complex and most toxic of the class, but is also the largest nonpolymeric natural product known to date. This Review begins with a brief history of the isolation of these biotoxins and highlights their biological properties and mechanism of action. Chemical syntheses are then described, with particular emphasis on new methods developed and applied to the total syntheses. The Review ends with a discussion of the, as yet unfinished, story of maitotoxin, and projects into the future of this area of research.

show abstract

Section: Synthetic Methodsmentioning

confidence: 99%

“…The mixed O,S-acetal radical cyclization/ring-closing metathesis sequence for the formation of cyclic ethers . [70] Scheme 21. The SmI 2 -induced reductive cyclization method for the formation of cyclic ethers (Nakata and co-workers, 1999).…”

Section: Synthetic Methodsmentioning

confidence: 99%

The Continuing Saga of the Marine Polyether Biotoxins

2008

View full text Add to dashboard Cite

show abstract

“…A reliable route to the left wing 3 is described in Scheme 6. Yamaguchi esterification [26] between the AB-ring carboxylic acid 27 [15] and the C21ÀC22 saturated E-ring alcohol 36, [15] and subsequent DIBAL reduction and acetylation, gave the O,Oacetal, [27] which was then converted to the corresponding O,Seacetal 38 by the action of iBu 2 AlSePh [28] in 56 % overall yield. Cleavage of the TBDPS-and TES-ethers of 38 with TBAF followed by selective reprotection of the primary alcohol afforded the secondary alcohol, upon which the cis-vinyl sulfoxide was installed by the action of NaH and (S)-alkynyl sulfoxide [29] to give the radical reaction precursor 39 in 80 % overall yield.…”

Section: Resultsmentioning

confidence: 99%

Practical Route to the Left Wing of CTX1B and Total Syntheses of CTX1B and 54‐deoxyCTX1B

Yamashita

Takeuchi

Kõyama

et al. 2014

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Ciguatoxins, the principal causative agents of ciguatera seafood poisoning, are extremely large polycyclic ethers. We report herein a reliable route for constructing the left wing of CTX1B, which possesses the acid/base/oxidant-sensitive bisallylic ether moiety, by a 6-exo radical cyclization/ring-closing metathesis strategy. This new route enabled us to achieve the second-generation total synthesis of CTX1B and the first synthesis of 54-deoxyCTX1B.

show abstract

“…After a considerable number of unsuccessful experiments with model systems, we found that the Sasaki protocol 49–51) was adaptable for constructing the EFGH-ring system from the E- and H-ring fragments following several crucial modifications and refinements. 52) The application of this modified Sasaki protocol to the synthesis of 1 was undertaken as shown in Scheme 4.…”

Section: Determination Of the Absolute Configuration Of Ciguatoxins Amentioning

confidence: 99%

Total synthesis and related studies of large, strained, and bioactive natural products

Hirama

2016

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

View full text Add to dashboard Cite

Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins.

show abstract

Convergent and stereoselective method for synthesis of O -linked oxepane ring system by intramolecular radical cyclization

Cited by 60 publications

References 35 publications

The Continuing Saga of the Marine Polyether Biotoxins

The Continuing Saga of the Marine Polyether Biotoxins

Practical Route to the Left Wing of CTX1B and Total Syntheses of CTX1B and 54‐deoxyCTX1B

Total synthesis and related studies of large, strained, and bioactive natural products

Contact Info

Product

Resources

About