Synthetic Studies toward Haouamine B: Construction of Indenotetrahydropyridone Skeleton

Okuyama, Kei Ichiro; Momoi, Yuichi; Sugimoto, Kenji; Okano, Kentaro; Tokuyama, Hidetoshi

doi:10.1055/s-0030-1259096

Cited by 16 publications

(5 citation statements)

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“…Considering the utilization of Baran’s protocol,2c we set indane‐fused dihydropyridone 3 as a key intermediate for 2 . On the basis of our preliminary synthetic studies on the initially proposed structure 1 ,5b the dihydropyridone would be formed through an intramolecular McMurry coupling6 of 4 , which should be derived through the ring‐opening of β‐lactam 5 . The cis ‐fused β‐lactam 5 should be accessible from mesylate 8 by an intramolecular Friedel–Crafts alkylation of the cationic species 7 .…”

Section: Methodsmentioning

confidence: 99%

“…Interestingly, unlike in the related report by Qin and co‐workers, who used an arylsulfinimine,9 the absolute configuration of the C2 and C3 positions was 2 R and 3 S , which was determined by comparison of specific rotations after transformation of 18 to a known compound 10. Having successfully constructed the consecutive stereogenic centers, we then focused on the intramolecular Friedel–Crafts alkylation of the tertiary alcohol 22 5b. After manipulation of protecting groups, the resultant compound 19 was subjected to the Merck protocol11 to provide β‐lactam 20 .…”

Section: Methodsmentioning

confidence: 99%

“…N ‐Benzylation and subsequent removal of the TES group gave the secondary alcohol 21 , which was converted to substrate 22 for the key Friedel–Crafts alkylation through Swern oxidation and diastereoselective 1,2 addition of an aryl Grignard reagent to the azetidin‐2,3‐dione 12. Conversion of the tertiary alcohol to its mesylate,13 which was treated with TfOH,5b unexpectedly afforded chromane 24 in 44 % yield. The reaction proceeded through a nucleophilic attack of the oxygen atom of the benzyl ether to form the six‐membered oxonium intermediate 23 followed by the removal of the benzyl cation 14…”

Section: Methodsmentioning

confidence: 99%

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Total Synthesis of (−)‐Haouamine B Pentaacetate and Structural Revision of Haouamine B

et al. 2014

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The enantiocontrolled total synthesis of (−)‐haouamine B pentaacetate was accomplished via an optically active indane‐fused β‐lactam, which was prepared by a newly developed Friedel–Crafts reaction. Subsequent cleavage of the β‐lactam and an intramolecular McMurry coupling reaction provided the core indane‐fused tetrahydropyridine, which led to the elucidation of the structure, as proposed by Trauner and Zubía.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Total Synthesis of (−)‐Haouamine B Pentaacetate and Structural Revision of Haouamine B

et al. 2014

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“…In 2011, Tokuyama's group reported the synthesis of indeno-dihydropyridone 4, 4 as a partial structure of the initially proposed haouamine B (2) (Scheme 1, ii). Professor Tokuy ama said: "This was the first project undertaken since I moved to Tohoku University.…”

Section: Matteo Zandamentioning

confidence: 99%

Synform Issue 2015/03

Zanda¹

2015

Synlett

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Yo ur op ini on ab ou t Sy nf or m is we lco me , ple as e co rre sp on d if yo u lik e: ma rk et ing @t hie me -c he mi str y.c omThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Dear readers,As anticipated a few months ago, Thieme Chemistry will soon start publishing brief 'News Articles', highlighting some of the most import ant eFirst papers published in SYNLETT and SYNTHESIS. These 'News Articles' will further increase both visibility and impact of research articles published by Thieme Chemistry. Although 'News Articles' will not formally be part of SYNFORM and will only appear on the Thieme Chemistry website, it's the SYNFORM editorial team who will identify suitable eFirst articles for this section. For this reason, I am particularly excited and pleased to welcome this new online feature that will enrich even further the content of our website. Moving to this new issue of SYNFORM, I am delighted to say that if this was poker we would be sitting on four aces here, and all of them from Asia! The first SynSTory describes a new protocol developd by S. Luo (P. R. of China) for synthesizing acyclic all-carbon quaternary stereocenters. The second SynSTory is again from the P. R. of China and specifically from Z.-X. Yu who takes us through his newly discovered gold(I)-catalyzed polycyclization reaction. And even the third SynSTory is from the P. R. of China, this time it's an enantioselective hydrogenation to produce α-hydroxy-β-amino acids reported by H. Lv and X. Zhang. Still from Asia, but this time from Japan, the fourth SynSTory reports on the total synthesis of a fascinating natural product, haouamine B, and its structural revision resulting from the work of H. Tokuyama. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Enjoy your reading! Editor of

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“…These studies proved that 206 is configurationally stable at the C,C aryl-aryl bond, 411 that leaves the appearance of two isomers of 206 to a conformational instability of the nitrogen atom (Scheme 33). The intriguing structural features of the haouamines together with an, as yet, unknown biosynthesis 412,413 and the exquisite antitumoral activities 81,411 have stimulated numerous synthetic efforts towards 12 and 206, [413][414][415][416][417][418][419][420][421][422][423] which culminated in two total synthesis of haouamine A (206). 411,424 After several failed attempts to close the strained paracyclophane unit using standard approaches, such as transitionmetal catalyzed biaryl couplings, Witkop photocyclization, and intramolecular alkylation, 424 Baran and co-workers adopted a completely new strategy constructing a saturated precursor via a pyrone-alkyne Diels-Alder cycloaddition.…”

Section: Haouaminesmentioning

confidence: 99%

Strained cyclophane natural products: Macrocyclization at its limits

2012

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Cyclophane natural products comprise an intriguing class of structurally diverse compounds. As inherent for all cyclic compounds regardless of their origin, macrocyclization is naturally the most decisive step, which defines the overall efficiency of the synthetic pathway. Especially in small cyclophane molecules, this key step constitutes an even greater challenge. Due to the strain imparted by the macrocyclic system, free rotation of the benzene ring(s) is often restricted depending on both the constitution of the tether and the aromatic portions. Not surprisingly, the synthesis of natural cyclophanes with their often outstanding pharmaceutical activities and the inherent issues associated with their preparation has attracted much attention among the synthetic community. In particular, it stimulated the development of new strategies for the ring-closing step, as often otherwise well established and robust reactions fail to perform effectively. In this review, we describe the challenges synthetic chemists are facing during the synthesis of this small, but structurally and biologically fascinating class of natural products, concentrating on the representatives exhibiting configurational stability. The main focus will be on the different concepts for the installation of the macrocyclic system, in most cases the central problem in assembling these extremely rigid molecules.

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Synthetic Studies toward Haouamine B: Construction of Indenotetrahydropyridone Skeleton

Abstract: Synthetic studies on haouamine B are described. The characteristic indenotetrahydropyridone skeleton was constructed by intramolecular Friedel-Crafts alkylation of mesyloxy b-lactam derivative and intramolecular McMurry coupling as key processes.

Cited by 16 publications

References 1 publication

Total Synthesis of (−)‐Haouamine B Pentaacetate and Structural Revision of Haouamine B

Total Synthesis of (−)‐Haouamine B Pentaacetate and Structural Revision of Haouamine B

Synform Issue 2015/03

Strained cyclophane natural products: Macrocyclization at its limits

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