Development of a strategy for synthesis of the unusual marine alkaloid sarain A

Sisko, Joseph; Henry, James R.; Weinreb, Steven M.

doi:10.1021/jo00070a035

Cited by 84 publications

(37 citation statements)

References 1 publication

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“…Those results induced us to attempt the synthesis of a few five-membered heterocycles from 1, since those compounds can be easily accessed through reacting appropriate ylides with a number of dipolarophiles [4][5][6] . As a matter of fact, those compounds are found in a large number of best-selling pharmaceuticals and numerous synthetic pathways to access them are reported in the literature and full mention of the corresponding literature is beyond the scope of this work [7][8][9][10][11][12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

1,3-Dipolar cycloaddition of azomethine ylide from Phtaloylimidophenylalanyl-2-hydroxymethylaziridine

et al. 2013

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Phtaloylimidophenylalanyl-2-hydroxymethylaziridine has been used as a starting material to yield azomethine ylide through thermal opening and was then involved into 1,3-dipolar cycloaddition reactions.Different five-membered adducts were obtained and were fully identified. The latter might be considered useful starting materials for further functionalization to provide novel compounds of biological interest.

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Section: Introductionmentioning

confidence: 99%

1,3-Dipolar cycloaddition of azomethine ylide from Phtaloylimidophenylalanyl-2-hydroxymethylaziridine

et al. 2013

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“…[11] Asymmetric [3+2] cycloaddition of a-aminoester Schiff bases with substituted olefins is one of the most efficient methods for their preparation in optically pure form, [12] thus making it possible to introduce various substituents on the pyrrolidine skeleton stereoselectively. [11] Asymmetric [3+2] cycloaddition of a-aminoester Schiff bases with substituted olefins is one of the most efficient methods for their preparation in optically pure form, [12] thus making it possible to introduce various substituents on the pyrrolidine skeleton stereoselectively.…”

Section: Introductionmentioning

confidence: 99%

“…The desired reaction proceeded in 82 % yield with moderate enantioselectivities ( Table 1, entry 1). When the reaction was conducted at 0 8C for 24 hours using 5 mol % of the silver catalyst, the desired product was obtained in only 37 % yield but with excellent exo selectivity and very high enantioselectivity ( [10][11][12], and use of diethyl ether (Et 2 O) was finally found to be the best. On the other hand, during our investigation on the ligand structures, interestingly, we found that use of SEGPHOS-type ligands afforded the exo adduct preferentially (Table 1, entries 3 and 4); (R)-DTBM-SEGPHOS (L4) in particular showed high exo selectivity (endo/exo = 4:96) and good enantioselectivity (84 % ee, Table 1, entry 4).…”

Section: Introductionmentioning

confidence: 99%

Chiral Silver Amides as Effective Catalysts for Enantioselective [3+2] Cycloaddition Reactions

Yamashita

Imaizumi

Guo

et al. 2011

Chemistry An Asian Journal

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Asymmetric [3+2] cycloaddition of α-aminoester Schiff bases with substituted olefins is one of the most efficient methods for the preparation of chiral pyrrolidine derivatives in optically pure form. In spite of its potential utility, applicable substrates for this method have been limited to Schiff bases that bear relatively acidic α-hydrogen atoms. Here we report a chiral silver amide complex for asymmetric [3+2] cycloaddition reactions. A silver complex prepared from silver bis(trimethylsilyl)amide (AgHMDS) and (R)-DTBM-SEGPHOS worked well in asymmetric [3+2] cycloaddition reactions of α-aminoester Schiff bases with several olefins to afford the corresponding pyrrolidine derivatives in high yields with remarkable exo- and enantioselectivities. Furthermore, α-aminophosphonate Schiff bases, which have less acidic α-hydrogen atoms, also reacted with olefins with high exo- and enantioselectivities. The stereoselectivities of the [3+2] cycloadditions with maleate and fumarate suggested that the reaction proceeded by means of a concerted mechanism. An NMR spectroscopic study indicated that complexation of AgHMDS with the bisphosphine ligand was not complete, and that free AgHMDS, which did not show any significant catalytic activity, existed in the catalyst solution. This means that significant ligand acceleration occurred in the current reaction system.

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“…However, despite the disadvantages mentioned above, to date only a few alternative methods have been reported and are anecdotally used, among these are: lithium in liquid ethylamine, [5] silver oxide/nitric acid in dioxane [6] silver(II) dipicolinate-H 2 O complex in a MeCN/H 2 O/MeOH mixture [7] and silver oxide/2,6-pyridine dicarboxylic acid in MeCN/H 2 O. [8] Thus, in case of highly functionalized substrates and more particularly in the field of total synthesis, selective and efficient cleavage of PMP protecting groups has turned out to be of primary interest.…”

Section: Introductionmentioning

confidence: 99%

Anodic Oxidation: An Attractive Alternative to CAN‐Mediated Cleavage of para‐Methoxyphenyl Ethers

Vaxelaire¹,

Souquet²,

Lannou³

et al. 2009

Eur J Org Chem

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Abstractpara‐Methoxyphenyl (PMP) ether is a very convenient protecting group for the alcohol function; however, its cleavage requires strong oxidative conditions. In this field, the use of powerful ceric ammonium nitrate has been widely described, despite the fact that its strong nature results in the formation of degradation products in acid‐ or oxidation‐sensitive substrates. In this paper, a new anodic oxidation method for the cleavage of para‐methoxyphenyl ethers in weakly basic medium is reported. This process is an attractive alternative to circumvent the use of ceric ammonium nitrate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Development of a strategy for synthesis of the unusual marine alkaloid sarain A

Cited by 84 publications

References 1 publication

1,3-Dipolar cycloaddition of azomethine ylide from Phtaloylimidophenylalanyl-2-hydroxymethylaziridine

1,3-Dipolar cycloaddition of azomethine ylide from Phtaloylimidophenylalanyl-2-hydroxymethylaziridine

Chiral Silver Amides as Effective Catalysts for Enantioselective [3+2] Cycloaddition Reactions

Anodic Oxidation: An Attractive Alternative to CAN‐Mediated Cleavage of para‐Methoxyphenyl Ethers

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