Synthesis of a key intermediate for the total synthesis of pseudopteroxazole

Yadav, J. S.; Bhasker, E. Vijaya; Srihari, P.

doi:10.1016/j.tet.2010.01.054

Cited by 23 publications

(24 citation statements)

References 43 publications

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“…Comparison of the 13 C-NMR data (recorded in benzene-d 6 , since elisabethatriene was analyzed in the same solvent) of the stereochemically defined 2b with those of elisabethatriene reported by Coleman and Kerr 7) indicated that the two compounds are apparently different from each other (even though some of their 13 C assignments were interchanged). In particular, the 13 C shifts of C-1, C-4, C-5 and C-8 deviated by more than five ppm (Table 1).…”

Section: Resultsmentioning

confidence: 84%

“…In particular, the 13 C shifts of C-1, C-4, C-5 and C-8 deviated by more than five ppm (Table 1). Therefore, the stereochemical assignment of elisabethatriene was incorrect and needs to be revised.…”

Section: Resultsmentioning

confidence: 99%

“…The (1S,2S,5R,2′S)-MOM ether 5 is a known compound that can be prepared from commercially available (−)-(1R,3R,4S)-isopulegol. 12,13) The use of (−)-isopulegol would lead to the antipode of the target molecule 2b (1S,4R,9R,11S configuration). This is acceptable in the present study, because we are concerned with the relative stereochemistry of 2a.…”

Section: Resultsmentioning

confidence: 99%

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Revision of the Stereochemistry of Elisabethatriene, a Putative Biosynthetic Intermediate of Pseudopterosins

Nasuda

Ohmori

Ohyama

et al. 2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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In the past, we have questioned the accuracy of the stereochemistry of elisabethatriene, a putative biosynthetic intermediate of pseudopterosins, in light of the configuration of elisabethatrienol isolated from Pseudopterogorgia elisabethae, which was represented as 1S,4R,9S,11S. We have reinvestigated the stereochemistry of elisabethatriene. Elisabethatriene with the reported 1S,4R,9R,11S configuration was synthesized starting from ( )-isopulegol in its enantiomeric form. The 1 H-and 13 C-NMR data of the synthesized compound differed from those reported for elisabethatriene. In addition to the fact that elisabethatriene is converted into pseudopterosins, this finding has allowed us to propose that elisabethatriene should have the 1S,4R,9S,11S stereochemistry, which is identical to that of elisabethatrienol.Key words elisabethatriene; elisabethatrienol; pseudopterosin; Pseudopterogorgia elisabethae Pseudopterosins are glycosylated tricyclic diterpenes isolated from marine octocoral, Pseudopterogorgia elisabethae, and more than thirty compounds in this class have been reported 1) since the first isolation of pseudopterosins A-D.2) Our group reported the isolation and characterization of pseudopterosins P-V as well as related non-glycosylated diterpenes, including elisabethatrienol (1) and seco-pseudopterosin K from P. elisabethae collected in San Andres and Providencia Islands in the Colombian Caribbean.3,4) It has been reported that pseudopterosin A displays potent anti-inflammatory activity 2) by inhibiting both phospholipase A2 and 5-lipoxygenase. 5)The biosynthesis of pseudopterosins was studied by Kerr's group. 6) These researchers reported the formation of a bicyclic compound named elisabethatriene (2a) upon incubation of geranylgeranyl diphosphate (GGPP) with a cell free preparation of P. elisabethae. Elisabethatriene has four stereogenic centers that were represented as 1S,4R,9R,11S (the pseudopterosin numbering system is applied). 7) These researchers also reported that incubation of elisabethatriene with the same preparation yielded erogorgiaene (3), 8) which was further converted to pseudopterosins 8) (Chart 1). Elisabethatrienol (1), a hydroxylated analogue of elisabethatriene, isolated by our group was determined to have the 1S,4R,9S,11S configuration on the basis of detailed nuclear Overhauser effect (NOE) experiments.4) It is of note that compounds elisabethatrienol and elisabethatriene have the opposite configuration at C-9, even though the stereogenic center disappears in the following intermediate 3. This finding raised the possibility that elisabethatriene could have the 1S,4R,9S,11S configuration (namely compound 4) rather than the reported 1S,4R,9R,11S configuration, since it would be reasonable to assume that the identical stereochemical mechanism is operating in the cyclization of GGPP leading to the two compounds. 4)In this article, we report the results from the reinvestigation of the stereochemistry that was reported for elisabethatriene. This study establishes that the stereochemistry o...

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Revision of the Stereochemistry of Elisabethatriene, a Putative Biosynthetic Intermediate of Pseudopterosins

Nasuda

Ohmori

Ohyama

et al. 2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…By preparing epimer 272 via Mitsunobu inversion, however, it was possible for the subsequent hydroboration (BH 3 •THF) to be directed by the secondary alcohol, thus favoring the correct face of the alkene. 335 Silylation of this material with functionalized chlorosilane 273 afforded alkyne 274 . Dess-Martin oxidation and triflation (KHMDS, PhNTf 2 ) gave rise to enol triflate 275 .…”

Section: Syntheses From the 21st Centurymentioning

confidence: 99%

Navigating the Chiral Pool in the Total Synthesis of Complex Terpene Natural Products

et al. 2017

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The pool of abundant chiral terpene building blocks (i.e. “chiral pool terpenes”) has long served as a starting point for the chemical synthesis of complex natural products, including many terpenes themselves. As inexpensive and versatile starting materials, such compounds continue to influence modern synthetic chemistry. This review highlights 21st century terpene total syntheses which themselves use small, terpene-derived materials as building blocks. An outlook to the future of research in this area is highlighted as well.

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“…79 Yadav e colaboradores descrevem a síntese de um intermediário chave para várias pseudopterosinas, utilizando uma reação de DielsAlder intramolecular de um dieno funcionalizado e um acetileno ligados por um espaçador com quatro átomos, formando um sistema tricíclico (Esquema 32). 80 O grupo de Dias relatou uma reação IMDA com a formação de produtos hidrindenos (Esquema 33), propícios para a síntese total da stawamicina. 81 …”

Section: Reações Intramoleculares (Imda)unclassified