Rapid Formation of Advanced Scaffolds from Phenols and Anilines

Synlett ◽  
2018 ◽  
Vol 30 (06) ◽  
pp. 647-664
Author(s):  
Sylvain Canesi
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Protecting Groups ◽  
Complex Structures ◽  
Protecting Group ◽  
Total Syntheses ◽  
Aniline Derivatives ◽  
Pinacol Rearrangement ◽  
Rapid Formation ◽  
Aromatic Systems

This article is an account of our efforts over the last decade to functionalize phenols and anilines at any position and to use these compounds to generate substituted aromatic systems and advanced unsaturated cyclohexanone moieties, enabling the rapid formation of complex structures. Total syntheses of numerous natural products involving such intermediates were achieved.1 Introduction2 ortho-Functionalization of Phenols and Aniline Derivatives Mediated by Iodanes (III) and Synthesis of Panacene2.1 Cross-Coupling with Aniline Derivatives2.2 Dearomative Cycloaddition of Arenes and Heteroarenes2.3 Total Synthesis of Panacene3 meta-Functionalization of Aniline Derivatives and Synthesis of Erysotramidine3.1 meta-Functionalization of Aniline Derivatives3.2 Total Synthesis of Erysotramidine4 para-Functionalization of Phenols and Applications in Total Synthesis4.1 Bimolecular Approach Mediated by Protecting Groups4.2 ipso-Rearrangement4.3 Oxidative Alkyl Shift4.4 Oxidative Prins-Pinacol Rearrangement4.5 Oxidative Prins-Type Reaction4.6 Total Synthesis of (–)-Fortucine4.7 Total Synthesis of Isostrychnine4.8 Total Synthesis of (–)-Strychnopivotine5 Development of a Functional Protecting Group

Skeletal Rearrangements as Strategies for the Total Syntheses of Indole Alkaloids

Synlett ◽  
2018 ◽  
Vol 29 (08) ◽  
pp. 1008-1013 ◽  
Author(s):  
Liansuo Zu ◽  
Xiaoni Xie
Keyword(s):  
Total Synthesis ◽  
Indole Alkaloids ◽  
Complex Structures ◽  
Central Theme ◽  
Total Syntheses ◽  
Pinacol Rearrangement ◽  
Skeletal Rearrangements

In this account, we summarize our recent efforts in the total syntheses of several indole alkaloids, including minfiensine, calophyline A, deformylcorymine, strictamine, and goniomitine. Our central theme is to utilize skeletal rearrangements as key strategies for generating complex structures.1 Introduction2 The Development of an Aza-Pinacol Rearrangement3 Applications of Aza-Pinacol Rearrangements in Total ­Syntheses4 Strategy Extension: The Total Synthesis of Goniomitine5 Conclusion

Protecting-Group-Free Total Synthesis of Anticancer (±)-Melotenine A

Synthesis ◽  
2021 ◽  
Author(s):  
Adisak Thanetchaiyakup ◽  
Hassayaporn Rattanarat ◽  
Sudaporn Aree ◽  
Tanwawan Duangthongyou ◽  
Tanin Nanok ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Human Cancer ◽  
Alder Reaction ◽  
Diels Alder ◽  
Protecting Groups ◽  
Protecting Group ◽  
Ring Closing Metathesis ◽  
Human Cancer Cell Lines ◽  
Diels Alder Reaction ◽  
Key Steps

Melotenine A, isolated from Melodinus tenuicaudatus, possesses significant anticancer activity against several human cancer cell lines. The synthesis of (±)-melotenine A was achieved without the use of any protecting groups in 11 steps with an overall yield of 7%. The key steps of our strategy were the Diels–Alder reaction to construct the tetracyclic framework and ring-closing metathesis to form the seven-membered ring of (±)-melotenine A.

Advances in catalytic and protecting-group-free total synthesis of natural products: a recent update

2020 ◽  
Vol 56 (61) ◽  
pp. 8569-8590 ◽  
Author(s):  
Rodney A. Fernandes ◽  
Praveen Kumar ◽  
Priyanka Choudhary
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Protecting Group ◽  
Feature Article ◽  
Total Syntheses

This feature article highlights the recently achieved efficient total syntheses of many natural products based on catalytic steps and protecting-group-free strategies, leading to overall economy and efficiency in synthesis.

Synthesis of Azido Acids and Their Application in the Preparation of Complex Peptides

Synthesis ◽  
2020 ◽  
Author(s):  
Ryan Moreira ◽  
Michael Noden ◽  
Scott D. Taylor
Keyword(s):  
Amino Acids ◽  
Natural Products ◽  
Total Synthesis ◽  
Cyclic Peptides ◽  
Protecting Groups ◽  
Side Chain ◽  
Coupling Reactions ◽  
Protecting Group

AbstractAzido acids are important synthons for the synthesis of complex peptides. As a protecting group, the azide moiety is atom-efficient, easy to install and can be reduced in the presence of many other protecting groups, making it ideal for the synthesis of branched and/or cyclic peptides. α-Azido acids are less bulky than urethane-protected counterparts and react more effectively in coupling reactions of difficult-to-form peptide and ester bonds. Azido acids can also be used to form azoles on complex intermediates. This review covers the synthesis of azido acids and their application to the total synthesis of complex peptide natural products.1 Introduction2 Synthesis of α-Azido Acids2.1 From α-Amino Acids or Esters2.2 Via α-Substitution2.3 Via Electrophilic Azidation2.4 Via Condensation of N-2-Azidoacetyl-4-Phenylthiazolidin- 2-Thi one Enolates with Aldehydes and Acetals2.5 Synthesis of α,β-Unsaturated α-Azido Acids and Esters3 Synthesis of β-Azido Acids3.1 Preparation of Azidoalanine and 3-Azido-2-aminobutanoic Acids3.2 General Approaches to Preparing β-Azido Acids Other Than Azi doalanine­ and AABA4 Azido Acids in Total Synthesis4.1 α-Azido Acids4.2 β-Azido Acids and Azido Acids Containing an Azide on the Side Chain5 Conclusions

scholarly journals Total Synthesis of Tiacumicin B: Study of the Challenging β-Selective Glycosylations

2020 ◽  
Author(s):  
cedric Tresse ◽  
Marc François-Eude ◽  
Vincent Servajean ◽  
Rubal Ravinder ◽  
Clemence Lesieur ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Protecting Groups ◽  
Ring Size ◽  
Efficient Removal ◽  
Full Account ◽  
Leaving Groups ◽  
Total Beta

<div>We report here a full account of the total synthesis of tiacumicin B (Tcn-B), a natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience with the synthesis of the tiacumicin B aglycone and on unique 1,2-<i>cis</i>-glycosylation steps. It features the conclusive use of sulfoxide anomeric leaving-groups in combination with a remote 3-<i>O</i>-picoloyl group on the donors allowing highly beta-selective rhamnosylation and noviosylation that rely on H-bond-mediated Aglycone Delivery (HAD). The rhamnosylated C1-C3 fragment was anchored to the C4-C19 aglycone fragment by a Suzuki-Miyaura cross-coupling. Ring-size selective Shiina macrolactonization provided a semi-glycosylated aglycone that was engaged directly in the noviosylation step with a virtually total beta-selectivity. Finally, a novel deprotection method was devised for the removal of a 2-naphthylmethylidene (Nap) ether on a phenol and efficient removal of all the protecting groups provided synthetic tiacumicin B.<br></div><div> </div>

scholarly journals Total Synthesis of Tiacumicin B: Study of the Challenging β-Selective Glycosylations

2020 ◽  
Author(s):  
cedric Tresse ◽  
Marc François-Heude ◽  
Vincent Servajean ◽  
Rubal Ravinder ◽  
Clemence Lesieur ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Protecting Groups ◽  
Ring Size ◽  
Efficient Removal ◽  
Full Account ◽  
Leaving Groups ◽  
Total Beta

<div>We report here a full account of the total synthesis of tiacumicin B (Tcn-B), a natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience with the synthesis of the tiacumicin B aglycone and on unique 1,2-<i>cis</i>-glycosylation steps. It features the conclusive use of sulfoxide anomeric leaving-groups in combination with a remote 3-<i>O</i>-picoloyl group on the donors allowing highly beta-selective rhamnosylation and noviosylation that rely on H-bond-mediated Aglycone Delivery (HAD). The rhamnosylated C1-C3 fragment was anchored to the C4-C19 aglycone fragment by a Suzuki-Miyaura cross-coupling. Ring-size selective Shiina macrolactonization provided a semi-glycosylated aglycone that was engaged directly in the noviosylation step with a virtually total beta-selectivity. Finally, a novel deprotection method was devised for the removal of a 2-naphthylmethylidene (Nap) ether on a phenol and efficient removal of all the protecting groups provided synthetic tiacumicin B.<br></div><div> </div>

The total synthesis of (+)-aspicilin using 2,3-butane diacetal protected butane tetrols via a chiral memory protocol

2001 ◽  
Vol 79 (11) ◽  
pp. 1668-1680 ◽  
Author(s):  
Darren J Dixon ◽  
Alison C Foster ◽  
Steven V Ley
Keyword(s):  
Total Synthesis ◽  
Lewis Acid ◽  
Selective Hydrogenation ◽  
Protecting Group ◽  
Ring Closing Metathesis ◽  
Total Syntheses ◽  
Key Steps

The total syntheses of the polyhydroxylated macrolactone (+)-aspicilin and a diastereoisomer have been achieved via a concise route, starting from the spatially desymmetrized (R',R',R,S)-2,3-butanediacetal-protected butane tetrol 13. The key steps include a regioselective silyl protection of 13 and a stereoselective Lewis acid mediated addition of allyltributylstannane to the equatorially disposed aldehyde of 4. Macrocyclization is achieved using ring closing metathesis, after which selective hydrogenation and protecting group removal yields the natural product.Key words: aspicilin, butanediacetal, desymmetrization, macrolactone, metathesis.

scholarly journals Total Synthesis of Tiacumicin B: Study of the Challenging β-Selective Glycosylations

2020 ◽  
Author(s):  
cedric Tresse ◽  
Marc François-Heude ◽  
Vincent Servajean ◽  
Rubal Ravinder ◽  
Clemence Lesieur ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Protecting Groups ◽  
Ring Size ◽  
Efficient Removal ◽  
Full Account ◽  
Leaving Groups ◽  
Total Beta

<div>We report here a full account of the total synthesis of tiacumicin B (Tcn-B), a natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience with the synthesis of the tiacumicin B aglycone and on unique 1,2-<i>cis</i>-glycosylation steps. It features the conclusive use of sulfoxide anomeric leaving-groups in combination with a remote 3-<i>O</i>-picoloyl group on the donors allowing highly beta-selective rhamnosylation and noviosylation that rely on H-bond-mediated Aglycone Delivery (HAD). The rhamnosylated C1-C3 fragment was anchored to the C4-C19 aglycone fragment by a Suzuki-Miyaura cross-coupling. Ring-size selective Shiina macrolactonization provided a semi-glycosylated aglycone that was engaged directly in the noviosylation step with a virtually total beta-selectivity. Finally, a novel deprotection method was devised for the removal of a 2-naphthylmethylidene (Nap) ether on a phenol and efficient removal of all the protecting groups provided synthetic tiacumicin B.<br></div><div> </div>

The Total Synthesis of Rhabdastrellic Acid A

2018 ◽  
Author(s):  
Yaroslav Boyko ◽  
Christopher Huck ◽  
David Sarlah
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Cross Coupling ◽  
Side Chains ◽  
General Strategy ◽  
Modular Approach ◽  
Linear Sequence ◽  
Generating Sequence ◽  
First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained <i>trans-syn-trans</i>-perhydrobenz[<i>e</i>]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a <i>p</i>-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

Short Protecting Group-free Syntheses of CDE Synthon of Racemic Camptothecin

2020 ◽  
Vol 17 (7) ◽  
pp. 588-591
Author(s):  
Pingxuan Shao ◽  
Wei Lu ◽  
Lei Wang
Keyword(s):  
Total Synthesis ◽  
Future Development ◽  
Protecting Group ◽  
Short Route ◽  
The Future ◽  
Tricyclic Ketone

A practical and concise total synthesis of tricyclic ketone 7 (CDE ring), a valuable intermediate for the synthesis of racemic camptothecin and analogs, was described (8 chemical steps and 29% overall yield). The synthesis starts with two inexpensive, readily available materials and is operationally simple to perform. It is worth mentioning that the reported protecting group-free synthesis, with advantages of a short route, would be helpful for the future development of industry-scale syntheses of camptothecin-family alkaloids.

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