The Second Total Synthesis of Diazonamide A

Nicolaou, K. C.; Rao, Paraselli Bheema; Hao, Junliang; Reddy, M. Venkat Ram; Rassias, Gerasimos A.; Huang, Xianhai; Chen, David Y.‐K.; Snyder, Scott A.

doi:10.1002/anie.200351112

Cited by 180 publications

(46 citation statements)

References 62 publications

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“…It is also conceivable that the 2,5-dihydroxybenzoic acid that exhibited higher enantioselectivity might also provide an additional asset for chitosan, favoring the recognition of this reagent by the catalyst. Other additives were also tested using the template reaction, which produced product 3a in good yields along with lower enantioselectivity (Table 3, entries [3][4][5][6][7][8][9][10][11][12][13][14]. Moreover, considering that the reaction temperature is related to the enantioselectivity, the reaction was conducted at 0 °C.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles

Hui

Liu

et al. 2016

Catalysts

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Section: Resultsmentioning

confidence: 99%

“…The 3-substituted-3-hydroxy-2-oxindoles have a stereogenic quaternary center at the C-3 position and a core unit that appears in many natural products and biologically active compounds [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles

Hui

Liu

et al. 2016

Catalysts

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“…As shown in the conversion of 55 to 60, those operations were a heteropinacol reaction initiated by the power of SmI 2 complexed to N,Ndimethylacetamide, in situ N-O bond cleavage to generate an amino alcohol, and subsequent peptide coupling. Not only did the successful realization of this cascade sequence represents the first macrocyclization using a heteropinacol reaction, it also fueled the completion of the revised structure of diazonamide A (49), an endeavor that finally proved its long-questioned structural disposition (30,31). Reflecting on this program, as well as the other programs described thus far from a broader perspective, these endeavors illustrate that virtually Scheme 2.…”

Section: Selected Total Synthesis Endeavorsmentioning

confidence: 87%

The essence of total synthesis

Nicolaou

Snyder

2004

Proc. Natl. Acad. Sci. U.S.A.

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For the past century, the total synthesis of natural products has served as the flagship of chemical synthesis and the principal driving force for discovering new chemical reactivity, evaluating physical organic theories, testing the power of existing synthetic methods, and enabling biology and medicine. This perspective article seeks to examine this time-honored and highly demanding art, distilling its essence in an effort to ascertain its power and future potential.Essence (és'ns) n. the most significant part of a thing's nature; the sum of the intrinsic properties without which a thing would cease to be what it is, and which are not affected by accidental modifications. (The New Lexicon Webster's Dictionary) A lthough the practice of total synthesis and the rationale behind its pursuit have changed throughout the course of its history, its most fundamental property has not. At its core, in its most essential form, natural product total synthesis is a vehicle for discovery, one that is perhaps unparalleled by any other endeavor in the realm of chemical synthesis (1-3). The reason follows: every natural product type isolated from the seemingly limitless chemical diversity in nature provides a unique set of research opportunities deriving from its distinctive three-dimensional architecture and biological properties. For instance, in the early part of the 20th century, efforts directed toward the synthesis of the antimalarial agent quinine (1) (Fig. 1) led to a sizeable body of knowledge regarding the construction of heteroaromatic systems and the unique physical properties of quinoline and piperidine rings. In more recent times, its structure has served as the basis for the design of several new classes of antimalarial drugs that have saved thousands of lives (4). Similarly, attempts to construct steroids such as progesterone (2) before World War II provided insights into how carbon-carbon bonds could both be forged and cleaved, with their partial or total synthesis ultimately rendering them available in quantities that are sufficient to propel them into useful drugs, such as the birth control pill, which is now used by millions of women around the world (5). In the 1950s, the highly sensitive ␤-lactam ring of penicillin (3) served as the impetus for John Sheehan (6) to develop carbodiimide-based reagents for the formation of peptide bonds. This discovery capped the first practical synthesis of this essential medicinal agent, enabled the synthesis of designed penicillins with activity profiles superior to the parent natural product, and revolutionized the entire peptidesynthesis field. In the 1960s and 1970s, members of the eicosanoid family of natural products, such as prostaglandin F 2a (4), served as the artistic canvas on which E. J. Corey was inspired to create the first catalysts capable of orchestrating asymmetric Diels-Alder reactions. It also was the arena in which he and his group developed the now ubiquitous family of silyl-based protecting groups, one of the most general and powerful methods for ...

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“…The amino acid origins of other heteroaromatic natural products are perhaps less clear. A more recent example is diazonamide A, [8][9][10][11] for which the putative biosynthetic precursor is the TyrValTrpTrp tetrapeptide, [12,13] which has to undergo a series of oxidation, cyclodehydration, and chlorination reactions to give the natural product. Although we have indicated the likely amino acid precursors to nostocyclamide, telomestatin, and diazonamide A as hexa-, octa-, and tetrapeptides, respectively, there is no implication that the biosynthetic pathway involves formation of all the peptide bonds before the various heterocyclization steps occur.…”

Section: Introductionmentioning

confidence: 99%

From Amino Acids to Heteroaromatics—Thiopeptide Antibiotics, Nature's Heterocyclic Peptides

2007

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Amino acids, the building blocks of proteins, also serve as precursors to a wide range of other naturally occurring substances including alkaloids, antibiotics, and, the subject of this Review, heterocyclic peptides. Simple alpha-amino acids are converted into complex arrays of heteroaromatic rings that display interesting and potent biological activity. The thiopeptide antibiotics, with their complex molecular architectures, are wonderful examples. In this Review we show how organic chemists have developed innovative methods for the synthesis of the heterocyclic ring systems, including routes inspired by the likely biosynthetic processes, and successfully assembled such building blocks into the final target molecule by application of orthogonal protecting groups and coupling methodologies.

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The Second Total Synthesis of Diazonamide A

Cited by 180 publications

References 62 publications

Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles

Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles

The essence of total synthesis

From Amino Acids to Heteroaromatics—Thiopeptide Antibiotics, Nature's Heterocyclic Peptides

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