Enantioselective Total Synthesis of Convolutamydines B and E

Nakamura, Tomoaki; Shirokawa, Shin‐ichi; Hosokawa, Seijiro; Nakazaki, Atsuo; Kobayashi, Susumu

doi:10.1021/ol052871p

Cited by 115 publications

(37 citation statements)

References 15 publications

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“…Incorporating protecting groups on the N1 of oxindole had no effect on reactivity, and gave the desired product in almost quantitative yield (99%) ( Table 2, entry 16). However, the electronic properties of the substituents at the isatin affected the yields strongly ( Table 2, entries [17][18][19][20]. Isatin with an electrondonating group only gave 60% yield.…”

Section: Resultsmentioning

confidence: 99%

“…Owing to the significance of this structural motif, numerous elegant synthetic methodologies have been developed [13][14][15][16][17][18][19][20][21] and aim to facilitate the synthesis of sufficient quantities of the desired natural products and related analogues for biological evaluation and structure-activity relationship studies, and thus finally contribute to the development of new therapeutic agents or important biological tools. The most direct approach to 3-substituted-3-hydroxy oxindoles is a nucleophilic addition of appropriate nucleophiles to isatins, such as the aldol reaction or an alkylation of isatins.…”

Section: Figurementioning

confidence: 99%

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Facile Creation of 3-Substituted-3-Hydroxy-2-Oxindoles by Arginine-Catalyzed Aldol Reactions of α,β-Unsaturated Ketones with Isatins

et al. 2013

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An efficient approach for the synthesis of 3-substituted-3-hydroxy-2-oxindoles has been achieved via an aldol reaction of α,β-unsaturated ketones and isatins using arginine as an organocatalyst. A range of 3-substituted-3-hydroxy-2-oxindoles were obtained in moderate to high (up to 99%) yields. These 3-substituted-3-hydroxy-2-oxindoles with an additional enone moiety provide an opportunity for further elaboration of the products and for potentially interesting biological activities. In addition, the formation of 3-substituted-3-hydroxy-2-oxindole 3a was confirmed by X-ray crystallography. The possible reaction mechanism reveals that the reaction proceeds via a double action process.

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Section: Resultsmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Facile Creation of 3-Substituted-3-Hydroxy-2-Oxindoles by Arginine-Catalyzed Aldol Reactions of α,β-Unsaturated Ketones with Isatins

et al. 2013

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“…Both syntheses started with the VMAR of D-valine derived N,O-acetal ent-33a and 4,6-dibromoisatin (219) which proceeded smoothly in 74% yield almost as a single isomer (>99 : 1 dr). 75 In 2009, the Kobayashi group published the synthesis of the AB ring moiety 227 of fomitellic acids using a VMAR between enal 225 and N,O-acetal 33a (Fig. 69).…”

Section: Stereoselective Transformations Using Silyl Ketene Noacetalsmentioning

confidence: 99%

The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

et al. 2014

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The vinylogous Mukaiyama aldol reaction (VMAR) allows efficient access to larger segments for complex natural product synthesis, primarily polyketides, through the construction of vicinal hydroxyl and methyl groups as well as di and tri-substituted double bonds in one single operation. In this review, we will highlight stereoselective protocols that have been used in natural product synthesis and cluster them into the four groups that can be obtained from different silyl ketene acetals or enol ethers. At the beginning, an overview on different stereoselective VMARs is presented; disregarding their applications in total syntheses.

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“…Then, a thorough study of this particular reaction uncovered significant rate enhancements by adding catalytic amounts of water in toluene, which permitted to obtain aldol (9) in 76% yield as a single diastereomer in a straightforward and consistent way [16]. The origin of this catalytic effect remains unclear, but it has proved to be general and has been successfully applied to other aldehydes [17]. …”

Section: Chiral Auxiliariesmentioning

confidence: 99%