Total synthesis of giffonin H by fluoride-catalyzed macrocyclization

2019 ◽  
Vol 6 (5) ◽  
pp. 704-708 ◽  
Author(s):  
Sooyoung Park ◽  
Seok-Ho Kim ◽  
Jin-Hyun Jeong ◽  
Dongyun Shin
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Synthetic Approach ◽  
Diaryl Ether ◽  
Key Steps ◽  
Highly Strained

First total synthesis of giffonin H, a highly strained 15-membered macrocyclic diaryl ether, has been achieved. Key steps include Ullmann cross coupling, (Z)-selective Julia–Kocienski olefination, and fluoride-mediated macrocyclization of TMS-alkyne and aldehyde. The strategy used for macrocyclization is an unprecedented and unique synthetic approach for cyclic diarylheptanoids.

A Concise Enantioselective Synthesis of (S)-Preclamol via Asymmetric Catalytic Negishi Cross-Coupling Reaction

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 860-862 ◽  
Author(s):  
Yun Zhou ◽  
Chunxiao Liu ◽  
Lifeng Wang ◽  
Leng Han ◽  
Shicong Hou ◽  
...  
Keyword(s):  
Total Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Drugs ◽  
Asymmetric Catalytic ◽  
Cross Coupling Reaction ◽  
Tertiary Carbon ◽  
Key Steps

A novel, concise, and efficient enantioselective synthesis of (S)-preclamol (87% ee, 51% total yield) has been developed. The key steps of this synthetic approach included cobalt-catalyzed asymmetric catalytic cross-coupling of α-bromo ester with arylzinc and the reduction of chiral ester to diol with a tertiary carbon atom. Moreover, it was demonstrated that our enantioselective Negishi cross-coupling was a powerful tool to construct stereogenic benzylmethyl center in chiral drugs on a gram scale.

scholarly journals Total synthesis of ochnaflavone

2013 ◽  
Vol 9 ◽  
pp. 1346-1351 ◽  
Author(s):  
Monica M Ndoile ◽  
Fanie R van Heerden
Keyword(s):  
Total Synthesis ◽  
Oxidative Cyclization ◽  
Experimental Conditions ◽  
Total Syntheses ◽  
Diaryl Ether ◽  
Key Steps

The first total syntheses of ochnaflavone, an asymmetric biflavone consisting of apigenin and luteolin moieties, and the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone have been achieved. The key steps in the synthesis of ochnaflavone were the formation of a diaryl ether and ring cyclization of an ether-linked dimeric chalcone to assemble the two flavone nuclei. Optimal experimental conditions for the oxidative cyclization to form ochnaflavone were established.

scholarly journals Total Synthesis of Surinamensinols A and B

SynOpen ◽  
2020 ◽  
Vol 04 (04) ◽  
pp. 84-88
Author(s):  
Ahmed Al-Harrasi ◽  
Satya Kumar Avula ◽  
Biswanath Das ◽  
Rene Csuk ◽  
Ahmed Al-Rawahi
Keyword(s):  
Total Synthesis ◽  
Allyl Alcohol ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Ethyl Lactate ◽  
Naturally Occurring ◽  
Cross Coupling Reaction ◽  
Synthetic Sequence ◽  
Key Steps ◽  
Single Approach

AbstractAn efficient total synthesis of the naturally occurring anti-inflammatory and antitumour 8-O-4′-neolignans, surinamensinols A and B, has been accomplished from commercially available allyl alcohol and (S)-ethyl lactate. The synthetic sequence involves a palladium-catalysed Suzuki–Miyaura cross-coupling reaction followed by a chiral Mitsunobu­ reaction as the key steps. This is the first report of the simultaneous stereoselective total synthesis of surinamensinols A and B through a single approach involving only six steps.

Total synthesis of (−)-exiguolide via an organosilane-based strategy

2015 ◽  
Vol 51 (40) ◽  
pp. 8484-8487 ◽  
Author(s):  
Hongze Li ◽  
Hengmu Xie ◽  
Zhigao Zhang ◽  
Yongjin Xu ◽  
Ji Lu ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Side Chain ◽  
Prins Cyclization ◽  
Key Steps

An organosilane-based strategy has been used to accomplish the total synthesis of (–)-exiguolide. The key steps involve: (1) geminal bis(silyl) Prins cyclization to construct the A ring; (2) silicon-protected RCM reaction to construct the macrocycle; and (3) Hiyama–Denmark cross-coupling to install the side chain.

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

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>

A Short Synthesis of the Plant Alkaloid 4-Methyl-2,6-naphthyridine

2019 ◽  
Vol 16 (12) ◽  
pp. 931-934 ◽  
Author(s):  
Alexandra Kamlah ◽  
Franz Bracher
Keyword(s):  
Pyridine Ring ◽  
Cross Coupling ◽  
Antirrhinum Majus ◽  
New Synthesis ◽  
Short Synthesis ◽  
Regioselective Oxidation ◽  
Key Steps

: A new synthesis of the 2,6-naphthyridine alkaloid 4-methyl-2,6-naphthyridine from Antirrhinum majus has been developed. Key steps are a regioselective oxidation of 3-bromo-4,5- dimethylpyridine to the corresponding 4-formyl derivative, and the annulation of the second pyridine ring by Suzuki-Miyaura cross-coupling using (E)-2-ethoxyvinylboronic acid pinacol ester as a masked acetaldehyde equivalent. This protocol gives the alkaloid in four steps starting from commercially available 3,4-dimethylpyridine in 15% overall yield. This annulation protocol should be useful for the synthesis of other condensed pyridines as well.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

Concise total synthesis of honokiol via Kumada cross coupling

2014 ◽  
Vol 55 (31) ◽  
pp. 4295-4297 ◽  
Author(s):  
Jada Srinivas ◽  
Parvinder Pal Singh ◽  
Yogesh Kumar Varma ◽  
Irfan Hyder ◽  
Halmuthur M. Sampath Kumar
Keyword(s):  
Total Synthesis ◽  
Cross Coupling

First Total Synthesis of a Fluorinated Calystegin

2010 ◽  
Vol 65 (4) ◽  
pp. 445-451 ◽  
Author(s):  
René Csuk ◽  
Erik Prell ◽  
Stefan Reißmann ◽  
Claudia Korb
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Competitive Inhibitor ◽  
Ring Closure ◽  
Target Compound ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Ring Opening Reaction ◽  
Ultrasound Assisted ◽  
Key Steps

A straightforward chiral pool synthesis for the first fluorinated calystegin is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs’ catalyst-mediated ring closure metathesis reaction. The target compound is a selective and competitive inhibitor for a β -glycosidase.

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